Depends on the jurisdiction. This is a conflict between freedom of speech and the reputation of the brand (which has financial value). Countries with a more recent monarchical past tend to value reputation over free speech, eg Japan but also Europe. The US has been a republic for a quarter millennium. Since MS is a US company, I think they wouldn’t even pursue this in the first place.

Generally, service providers are exempt for liability for such things if they follow certain rules of conduct. EG the US DMCA says that you are not liable for copyright infringement, if you comply with takedown notices. I’m not sure how that works for trademarks in the US.

Generally, though, you should expect to be held responsible for any infringing content on your service, once you learn/are notified about it. You will be treated as if you had created the content yourself. That means that you will have to make the argument in court that the use of the trademark was legal. And if you lose, you will pay the damages.

Questions?