No it's more along the lines of "Just because we're amateurs doesn't mean we have to act amateurish" - I can't remember whose quote that is.
"Suck it up and move on" is a good advice. The more your comic gets read, the more there are people who don't like it, and people who are compelled to comment about it. If you have any sort of popularity, the simple google search gives you all kinds of comment, from constructive criticism to "THIS IS CRAP THIS GUY MUST BE RETEARDED!!11!" kind of quips on some 4chan-like board or wherever. If one's gonna sulk and cry or go to crusade every time they get something like this, they'll have a full time job and a stressful one at that.
"Suck it up and move on" means learning to accept negative opinions and not getting emotional about them every time. To an author who displays his work publicly, this is as important quality as, say, knowing how to draw. Of course it's nicer if you're capable of looking back at criticism and getting something useful from it, but even if you're not you should still be able to receive criticism without acting like a jack-ass.
Anyways I think that if you ask for a critique, you don't have right to complain when you get a bad one. That just makes you look like one of hundreds of guys who request a reviews left and right in a bid for promotion, and then get honestly offended when they realise that not everyone sees their comic the way they do. Or like it as much as they do. Duh.
There's an option of checking what kind of review you can get somewhere. If you want to request a review on some site, read a few of articles from it first, get an idea of what kind of opinion you can get there. If you don't have respect for their opinion, why should you waste your and their time, and put yourself through criticism you won't find useful? On the other hand, if you do have respect, then if you get a bad review and get all dismissive about it retroactively, then... well, that'll be very cute.
Webcomic Above thread is a sort of random choice and yeah, you may expect that the one that gets to review you is gonna pat your shoulder and whisper that everything's ok, but there's no such guarantee. Serge does like half of those reviews anyways, and he means business.
Seriously, if you asked for a review yourself, and then later want to discuss it, ok but be sure to check if your humility is in place. Save sarcasm for another occasion, as well as passive-agressiveness and thinly veiled attacks.
Personally, I don't think there's anything wrong with having a little fire in your words when you're speaking about anything that's important to you.
Yeah and then the guy you talked to is gonna put a little more fire, and then you're gonna put even more, and we'll have a nice flame war that'll have to be locked.
In forum discussion emotions tend to rise exponentially, and unless someone (like Buster here) steps back and tiptoes 'round the other guy, it usually ends bad.