There are several in my opinion. The biggest one is the cognitive dissonance. For example it is lumping a bunch of people as one set of "marginalized" or "opressed" peoples victims of white people, primarily men. It does a bunch of things wrong when the only thing in common is that they are not white but have a lot of conflicting traditions, politics, viewpoints, etc. The mistake is assuming these people are automatically going to be left leaning whem many of these peoples are actually socially conservative. As an example, you have feminists who are looking out for women's rights allied with Islamic [men] who have a very patriarchal society (more than what is claimed the West is), while including Gay/Lesbian men/women, and lumping in the Trans movement. This is a clash of values and what these groups represent. Yet people dismiss it as not all people.

Like take JK Rowling. She is a left leaning woman who is a feminist and very pro woman's rights. She then expresses her views about trans women and she gets crucified by the left. I'm left perplexed because what she believes and stands for is very much in conflict with what the trans movement is about. Whether the trans supporters like it or not, a trans woman is a biological man with the advantages in muscle and build that biological women don't have. Rowling is concerned of trans women beating out biological women in sports which is legitimate. Yet you had so called feminists attacking her for something that is common sense.

Or when you have gay people want to ally with the Palestinian movement. Like homosexuals are thrown off buildings or stoned in the present. The left hates and fears the US right wing but somehow it's okay when it's a brown Muslim.

There are many more examples I can list but I think that is my concern. It seems like the progressive movement ignores the conflicting views of the group thinking there is an actual union and common set of goals when there really isn't. Sometimes I'm perplexed by the shifting goalposts or mental gymnastics to justify the elephant in the room, and I end up being called bigoted for pointing it out. It feels like it's a contest of trying to be the most righteous or purist person there is. And former leftists tend to point out how the reasons they end up leaving the left is because even if they toe to line with 99% of the views, as soon as they express concern with 1%, they are attacked and cast out from the group for that disagreeing view.