It definitely was a rude question, but why are his claims any less true? It's corroborated in a very large amount of reporting I've read so far. He turned me around a bit when he was dead right on Hakkanpaa and very rightly called out the signing. Truthfully he asked the question a very large portion of the fan base was thinking and I don't see why he shouldn't do that. Maybe with more decorum, sure, but it's a fair question.
It was a lousy gotcha kind of presentation by Simmons. But as you say "It's corroborated in a very large amount of reporting I've read so far." I too have seen, heard or read things like that. 19 out of 20 seems excessive as a higher percentage are wait and see from what I've seen. I'll bet there are a bunch of aspiring GMs around the league saying to themselves "WTF just happened in Toronto?"
Is there any merit to their concerns?:
In six seasons of junior hockey (SCTA, GHJHL, MJAHL,BCHL,OJHL), I think he played 3 playoff rounds that his team lost
Aside from his stats company, his only jobs in hockey were in 5 years total in AZ as ass't GM & GM
His drafts in AZ were not very good (2016, his best, was days after he got the job so it is questionable how much input he provided)
His trades in AZ were generally not great/good
AZ pts% was below .500 during his time - he never GM'd during a NHL playoff appearance - his 5 AZ NHL teams (one as ass't GM) qualified for one playoff round played after he left that they lost
His AHL team made the playoffs one season of five and lost in the 2nd round
He's been out of hockey 6 years
Chayka was suspended from the NHL for a year for "conduct detrimental to the league and game" and for breaching "his obligation to the club" by pursuing opportunities with other clubs while still under contract with the Arizona Coyotes.
Coyotes lost 1st & 2nd round picks for hosting a private scouting combine prior to the draft during Chayka's watch
Apparently, he's fending off tampering allegations days into his job with the Leafs.
In his six seasons of junior, his 5 seasons overseeing the AZ AHL team and 5 seasons overseeing the AZ NHL team, he has won only one AHL playoff round that I could find. He's never won any championship or tournament in hockey as a player or executive that I could find.
So his career facts support the question "is this the best the Leafs could do?" as not being an unreasonable question.
As a Leafs fan, I hope for the best and that he's successful. But I can certainly understand the concern and pessimism as it is well founded.