Microsoft at least is the devil you know. It’s like the problems with staying on Musk’s Twitter are known - but some random mastadon server could have a literal who in charge; who could do anything (or disappear as Thomas the CEO seems to have done - check Sodor mayhap).
You would choose a company that thinks Open Source is "literally cancer"[1] to support your FOSS project, rather than an unknown person: You need more faith in humanity.
Is Github more stable as a platform, sure. Does Github ban a higher percentage of projects than are effected by unreliable 3rd parties, unquestionably!
My own personal experience is that about 5% of the FOSS projects I have hosted on Github have received a DCMA takedown notice, normally from people trying to monetize in the same domain. (Including a website for a local sports club and an Android app for learning fingering of an obscure musical instrument). Less than 0.3% of all FOSS projects I have hosted elsewhere have received a S&D or DCMA or any equivalent...
[1]https://www.theregister.com/2001/06/02/ballmer_linux_is_a_ca...
Eh, I can understand not wanting to be at Microsoft's mercy. And ideology oriented projects are likely to take issue with hosting on a platform that is not itself open source.