I'm not here to defend racism, phobias, or any other kind of discriminatory behavior. But if you look deep enough into anybody, you're going to find something you or someone you know doesn't like. I can guarantee it. Are some of the original developers of a specific set of software "problematic"? Yup. Have more contributors come forward and added to the software in meaningful ways since then? Yup.

Do you use Linux? Windows? Mac OS? Do you use Ethernet? Wifi? What about IP, or TCP, or even application protocols like HTTP? Do you enjoy TLS and AES encryption? What about the Internet as a concept? Every single one of these was developed by fallible people, funded by organizations I bet you'd have problems with. The military industrial complex has contributed heavily to every single one of the above technologies.

And just for the record, a lot of the people that originally designed the ActivityStream and ActivityPub standards were people concerned about marginalized Internet users. Use the software, choose an instance that's like-minded, contribute improvements where you have expertise, and move on. The original developers of the Lemmy software don't matter, nor do their politics or their biases. They simply wrote some Rust and Javascript to run a webserver and interface that saves data to a database. What you do with that tool is what really matters.