In an ideal world, intent shouldn't really matter (it does matter in our world, for pragmatic reasons, but it shouldn't). If the results of one's actions cause harm, one should be dissuaded from continuing / repeating those actions, regardless of intent.
You do rightly point out the reason intent does tend to matter in reality: it's that the response to RMS' actions are punitive ("you deserve bad back"). And ideally people shouldn't be punished for unintended mistakes; they should instead be helped (sorry if that comes across condescending to the offender, but it's true).
Focusing on intent instead of outcomes is still regressive or reductive in either case though.
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Aside: this is somewhat off-topic and probably a debate for a separate comment/thread here, but I do want to note I use the term "harm" above very intentionally; I don't believe "offensive" is the correct term here at all. Being offended is not harmful. I think a lot of aspects of PC/cancel-culture focus on protecting those who are "offended", which is nonsense. If you're not offending people in this world, you're not living. But doing actual harm goes beyond that, and should be addressed. And I do believe RMS' actions were harmful.