Just in case for those skimming the headline, note the quotes used in it. The author does not claim to know whether or not the company is actually involved in filing these requests, though as he points out, it is plausible.

Someone purporting to be United Healthcare is filing DMCA requests

If it is really the health insurer filing these notices, it wildly oversteps any legal rights the company might have, but if there’s any company willing to preemptively breach the law and dare the other side to spend their limited resources trying to protect their rights it would be a health insurer.