I wonder which article of the sanctions this falls under. It seems to me that github & other cloud services are a sort of dual-use technology, where you could certainly imagine them being used in ways to support the Russian occupation, even though most users are certainly just civilian bystanders, like Kashkin.
With all sanctions, one risk is that it just displaces the demand towards alternative services that are hosted in either neutral or hostile countries. As this fallback capacity is increased, it then blunts the impact of future sanctions. The same thing applies to financial sanctions, where I'd guess someone like China or Russia probably has alternate financial network for everyone frozen out of the SWIFT network. In fact, Wikipedia cites a reference to an existing Russian alternative:
Anyway, I feel for these unfortunate guys, who are suffering from the fallout of their countries' policies. All the more so, if they don't even support said policies. I think we can all empathize with that part.