I think your perspective is interesting because, to me, it kind of encapsulates the divide over Burke and his management style. The Tavares thing, for me anyway, was never about the disappointment that he wasn't able to pull it off. When Burke said it was his goal my reactions were that A) It was stating something relatively benign, as it made a lot of sense for him to try and acquire a player as good as Tavares but also B) Kind of pointless, because there was no real chance the Islanders were going to trade that pick.
So the issue, as I saw it, wasn't being disappointed that Burke wasn't able to pull off the impossible but rather it was puzzlement as to why he felt the need to make it known he was going to try. To me, it seemed to do nothing but set him up for failure and create an air of disappointment around whoever it was the Leafs ended up picking.
For someone who had a very, very high opinion of Burke then, yeah, I could see how there would be a disappointment that he isn't able to do a lot of the things he says he's going to try and do but for someone who always sort of tried to judge him based on what he actually did with the team then the issue has really been about his dealing with the public and what it creates for the team in terms of expectations and pressure.
A good example, I guess, might be his stated aim of "retooling" and putting a good team together in a short period of time despite the lack of a base. The negative reaction, on my end anyway, was never that he didn't pull it off but rather that it was not a good thing to try in the first place.
So, yeah, if you came in with a hero worship of Burke then I could understand not getting why people reacted to his "failures" so harshly but, I think, the issue has never been that. The issue has more been about the actual effects of what he says.
Morgan Rielly just realized a lifelong dream by being drafted. More than that, he did it in the top 5 in the draft and with a Canadian team. I bet he's on cloud 9. There's no need to pump him up any further. The only thing Burke said is going to do is create what is probably an unrealistic level of hype for him among the rank and file.
Burke's shortcomings as a GM are another matter but, at least to me, this is another example of Burke really not being very good at dealing with the media and the nature of this team's fanbase.