Couple of reasons for me.

The site is not Apple friendly. Uploading pictures is a major pain in the a$$. Other forums are effortless if you want to upload a picture quickly from your phone.

The info links that pop up are beyond annoying while trying to post or view

It’s the same 5 people who respond with their opinions on engines and if you don’t agree with them you are deemed the bad guy...

I think it’s time for Moparts to step up or step out