He invoked controversial right-wing populist slogans in the project README. Yes, that is involving politics, and doing so in a way that is guaranteed to put a lot of people off.
He can be political even in ways people finds offensive, and still have people prepared to still engage with his projects, but he can't do that within the project and expect people to ignore it. It's his choice. He appears to have chosen to double down on being controversial and driving people away from the project.
> why you think someone who pledges not to discriminate against people for politics
The "no DEI" bit is a common "slogan" from people who by many are seen to want to ignore discrimination and pretend it isn't a problem, often because they are seen as quite happy for discrimination to continue. As such, to a lot of people when someone makes a claim like that adjacent to claiming not to want to discriminate, it rings hollow, and in fact often signals to them that the person using that language is likely to either be a racist or is fine with racists.
You don't need to agree with those views. You're free to find that interpretation ridiculous or offensive. But when you try to defend this project, you ought to at least understand that this is how it gets interpreted by a lot of people, and this is why the project is mired in controversy, and will remain mired in controversy as long as the project presents itself in this way.
If his intent seriously is to genuinely not discriminate, then his choice of working is exceedingly poor and shows a lack of understanding of the politics involved.
He has now had plenty of opportunity to read reactions to it, and has still chosen to leave that language in place. To me, that is strongly negative signal - either he doesn't care about the reaction, or is being stubborn and willing to push people away, or he's fine with people seeing him that way. Either way, it's not going to do anything good for this project.