There’s a difference between negative feedback and being rude. The former is necessary when crappy work gets submitted, the latter drives people away before giving them a chance to improve. The way you phrased your question implies that there’s an exclusive choice to be made here, which is not the case.

How much toxicity a project can tolerate is in inverse proportion to how important it is, but every project has its limits no matter what.

I think this is a wise choice. Either Torvalds needs to figure out people better, or he needs to bring in a lieutenant who can handle people more effectively than he does.