I've always opposed the settlements personally. But I do also understand the complexity, and I know for a fact that the settlements are not the reason for Arab opposition to Israel.
You asked your question fairly and it deserves a real response. I apologize but I will have to give you a longish answer, because the stereotypical sound bites obscure the real issues.
The Arabs tried to annihilate Israel in two separate wars long before Israel even had any control of the territories. And Israel offered the territories back in 1967 in exchange for peace and the Arabs said "no". And - the Gaza experience in which Israel not only withdrew every single settlement but also removed even their Army presence from Gaza - resulted in the exact opposite of a shift toward peace. The Palestinians took it as a sign of weakness and redoubled their commitment to annihilation of Israel.
So - while I don't believe the Settlements are justified, I also know they are not the reason there is no peace.
It was not that long ago that the majority of Israelis were repeatedly willing to dismantle the settlements if it could lead to a real peace.
Now, however, after the Gaza experience - Israelis have a different concern. If they withdraw from the settlements and give more autonomy to Palestinian in the territories -- what will stop them from simply inviting Iran and Hezbollah in and putting more missiles on every Israeli border?
So - I think it is error to imagine that in today's climate that there would be any "peace and security" for Israel if they abandoned the settlements. Gaza suggests quite the opposite, and Israel is so tiny that they can't afford to ever lose any war. They would be overrun and likely slaughtered.
So any BDS people who actually think somehow forcing Israel to withdraw the settlements would lead to peace is imo very naive and willing to take the risk on the backs of Israeli Jews.
I think it's also naive of the BDS crowd to think that Israel would in fact take steps that would allow Iran in the heart of their nation - no matter what the rest of the world does to Israel in terms of sanctions etc. Because they see such moves as primarily suicidal.
At most - Israel might withdraw settlements - but they will never without a true peace withdraw their military and check points etc. They will continue to blow the shit out of Iranian arms shipments etc etc. It really is a matter of life and death for them. And - then the BDS crowd will say it's not the "settlements" but the other defensive measures Israel takes that they will target as the "problem"
Most BDS people I have deeper conversations with however don't even believe or want that -- they want the destruction of any Jewish refuge state. They argue about "Palestine from the River to the Sea" -- which means Jews living in the same subjugation they lived in throughout most of Arabia for the last thousand years or so.
From my view, the largest stumbling block to peace is that the Arab leadership has not embraced true peace with Jews. It's rooted in their faith concepts that Muslims must dominate, Sharia law relegates Jews to very low status (can't even testify in court as a full human for example) -- and their institutional schools, media and universities are still teaching their population that Jews are "pigs and apes". PEW surveys across Arabia reveal that even the most educated deeply believe the worst anti-Jew conspiracy theories ever thought of. Their idea of "peace" is a Muslim state in which they would provide what they see as reasonable treatment to the Jewish minority.
finally - on the anti-semitism in the BDS movement: First, I've already explained that the movement is focused on forcing Israel to take suicidal steps, which no one in those same movements would ask of any non-Jewish nation. So when they argue that Israel must stop the blockade and allow Gaza to import arms from Iran - it shows bigotry.
Second - many in that movement also rely on anti-semitic tropes -- calling the Jews "nazis" for example; accusing them of "genocide"; horrible conspiracy theories ranging from "killing Palestinians to sell their body parts" to "training sharks to attack Palestinian swimmers"; and of course there is always lurking that "nefarious Jewish "control" issue."
They make false comparisons to South Africa - ignoring that more Arabs obtain high learning degrees in Israel than anywhere else in the middle east - ignoring Palestinians on the Israeli Supreme Court, in their legislature, working as doctors and lawyers and teachers in Israel etc.
I've even seen BDS people claiming that all the positives that Israel does, is some sort of "ruse" cooked up for "hasbarah" PR purposes. For example, Israel is by far the most Progressive nation in the middle east on gay rights -- but if it's ever mentioned the BDS crowd yells "pink washing" -- as if it is another nefarious conspiracy rather than the societal egalitarian embrace that it actually is in Israel.
All of these reveal anti-Semitic bigotry, but when challenged the purveyors fall back on the very false claim that "any criticism" of Israel results in a charge of bigotry.
And - there is something recognizable about the self-righteous passion the BDS crowd has to right the "wrong" of Jewish Liberation -- when at the same time they have zero passion for other nations' problems -- so many of which make Israel's look small by comparison. This too certainly raises the clear possibility of underlying racist motives. Just like Omar did in her statement that about politicians who support Israel on the merits.
Not all BDS people are anti-Semitic, but there is deep antisemitism aligned with the movement. Rare do I see discussion from them on the issues that doesn't at some point start including anti-semitic concepts.