I've been dealing with mental illness for a lot longer than I've known I was queer. Not all mental illness is caused by discrimination or other external factors.
More context is needed when it comes to co-rumination. LGBTQ+ people are being specifically targeted by legislators, and it would be unreasonable for them not to regularly discuss it in their communities. There's a difference between activism, sharing information, and rumination. I think the article should have taken some time to explain how to identify the differences and how to know when to take a step back and take care of yourself.