It absolutely was not in poor taste.

<Maroczy>'s unnecessarily sobering reply was what was in poor taste.

A tactless comment that took your lighthearted joke which was more a celebration of this guy's life and turned it into a grim remark on his untimely death.

I guess "poor taste" is in the eye of the beholder. At first I thought <aw1988>'s comment (joke) was in poor taste (as he admitted himself), and maybe he felt the need to apologize to anyone he offended. I'm sure he was only trying to provide some levity to a serious subject. But in my opinion, <sharpnova>'s shaming of <Maroczy> for clarifying what "the big C" means (not Carlsen, in this case) is a far worse crime. Stating the fact of Ivanov's condition (for anyone who may not have known) -- in a one word answer! -- did not warrant such verbal abuse intending to inflict guilt. If the "C" word is "unnecessarily sobering," maybe it's best not to joke about it!

But block away, <sharpnova> (last seen in 2017). It may be enlightening to read the profile page of this person:

"I find many aspects of most of the people here very annoying and childish."

I had the great pleasure of playing Igor back in 1986, in San Jose, California. It was a Master/Expert tournament (I was an Expert), and we were paired in the first round. I had Black, and played a King's Indian Defense. He played the Petrosian variation (1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 0-0 6. Be2 e5 7. d5). Unfortunately, I misplaced or lost the game score, but the gist of it was that he had played Bg5 early on (pinning my Nf6 to my Qd8), and to get out of that, I had played the moves ...Bg4 and ...Qd7. At some point, I played the moves ...Ne8 and ...f5. At a key point, Igor played a fairly quick c4-c5, a blunder! I played f5-f4, trapping his bishop, still on g5! I managed to win the bishop (after h7-h6 and ...hxg5), but as a result, my own dark-square bishop (on g7) was hemmed in by my own pawn chain. I later (somewhat cleverly, I thought) sacrificed a knight for two pawns, which allowed me to free my Indian bishop. Everything was going my way... up two pawns in a bishop (mine) vs knight endgame, and I made time control on move 40. The problem? I blundered on move 41! Moving much too fast, considering I wasn't in time pressure anymore! (But pulse racing.) I missed that he had a knight move (42. Nc5!), attacking my b7 pawn, the loss of which would have given Igor a winning passed pawn. I couldn't capture said knight with d6xc5, because he would then play d5-d6, soon queening his d-pawn! Because my bishop at that point (as well as my king) was out of position, I believe on b2 where it had captured a pawn. So bottom line, I went from a sure win to dead lost, completely skipping over any drawing chance.