The first is having an organisation that can't be trusted hold "your" coins for a long period of time. It is a bad idea because you could hold the coins yourself (that is, there is a less-bad alternative).
The second is buying coins from that same organisation. This may not be a bad idea, because the risks involved in the short transaction may be very low, and you may not have a better alternative.
Again, my point is that regardless of whether either of these things is a “good idea” or “bad idea”, it is not fair to call exchange insolvency a good thing; *one* reason here being that the second “thing” “has to exist” for the ecosystem to work.
I really did not expect this to be so controversial a point, but I suppose I haven’t done the best job expressing it.
But I think the reality is you just misunderstood the original comment. The original comment was saying that it was good that people were withdrawing their crypto, not that it was good that any particular exchange had become insolvent. Only after I read your edited original comment did I realise that this is what happened.
When a crypto exchange fails I always say "That was unsurprising. Remember to hold your own coins." A lot of other people say similar things.
I do not say "This is a good thing. I'm sure that now that Failed_Exchange_1001 has failed people will finally learn to hold their own coins." I don't think I've heard many people suggest that.
Well. looks at the dozens of comments in this thread. My bad.