Ba'athists are not chauvinists they are Arab nationalists, wanting to unite the Arabic speaking peoples against colonialism. However, they live in diverse countries with significant numbers of non-Arabic cultures. Previous iterations of the Arab Nationlist movement like the Nasserists wanted to immediately unite Arab majority countries while the Ba'athists realized they need to first unite the cultures within their countries and then building a greater indigenous state in the region to fight European (and Turk) colonialism. So the Ba'ath in Iraq started a popular front with the Kurdish communities, but the tensions with Kurds, Arabs, and Persians in the Levant was already strained by Imperialist strategy before the Ba'ath seized power. The popular front was in the right direction of peace and unity until the war with a Iran, who's new government hated the Arab socialists.

Now, on the gas attacks, we have to know a few things. The US only blamed Iraq for the attacks retroactively, and in fact initially blamed Iran. The only witnesses of the attacks from the outside were Iranian journalists, working alongside British "journalists". When the US switched to blame Iraq, in preparation for the sanctions they would lay on Iraq in the 90s to choke out the Ba'ath, they claimed that they knew it was Iraq the whole time and only blamed Iran because Iraq was their "ally". Neither Iraq nor Iran ever claimed the US to be an ally. Iraq had been fighting Kurdish insurgents who were being organized by US/UK and Iranian intelligence, Iraq had real reasons to be fighting in Kurdish territory in the north. The Iranians had been occupying the village up until the day of the attack, where they quietly retreated in the morning before the attack. Now we also have the false flag accusations against Syria and Libya, where British intelligence worked with the so-called White Helmets to fabricate a chemical attack to justify the American occupation in the Kurdish region of Syria as well as NATO funding for ISIS, I mean the "moderate rebels".

A lot of these attacks towards the Ba'aths come retroactively. To me, an obvious attempt to discredit the Ba'ath based on inflating the "relationship" between the US and Iraq. By pretending to be an ally of Iraq, and acknowledging some of the US's bad history of intervention, they were able to divide the left on Iraq and later Libya and Syria. "We were bad but now we are good and we gotta get rid of the monsters we've accidentally created while doing realpolitik". I think even people like Parenti fell for this. Meanwhile the only real theme in these events is that the US and British supported rebels against anti-Imperialists governments wherever they could.

No, Baathists were originally Arab patriots who went for decolonization movements and were secular. Later infighting and anti communist sentiments started growing inside baath which made them corrupt .
https://youtu.be/gYrSd1UkS50?si=6goRV1Q6VcunNRcB this is the anthem of baath Syrian party. No they were not chauvinist, Saddam had different reasons to gas kurds , kurds wanted a seperate ethno state for them. Currently same thing Syrian kurds want from Assad. To fracture the country into little ethno states.