Good for him, no donations should translate in to obligations, they're donations , voluntary and are considered to be a reward for services rendered in the past, not the future. Typically when someone is as driven as this and you get the output of all the labour that went in to it the proper words are 'thank you' and if you feel like rewarding the creator then that's great. But that does not entitle anybody to future…
Personally, I'd have no problem blowing people off who ask for more than they were promised if it got to this point. Then again, that might bring negativity to the community, so I can see how the decision to just stop personal donations makes sense.