the main criticism is when aliases are used to flame another poster in a really ugly way.  Even though one's basic handle is an alias of a sort, it's still your basic board "personna," the way other regulars on the boards know you and what you stand for.  So it's considered gutless and  lacking in  credibility to flame from behind an alias.
Having said that, I think the boards would be poorer if there were no aliases.  I mainly use mine for humorous purposes and have outed myself as being behind them because I don't  care.  But I'll also admit to having used an alias to flame someone I considered nasty or ridiculous because I didn't want to create a permanent enemy on the board.
Just to be up front, here are a few of mine that are well known:
The Cunning Linguist
Conan The Gramarian
J. Edgar Hooker
Doctor Boner
Asshat Alert
inooky46
JackMeeoff
Izzy Clitoris
RUShittinMe
Shit from Shinola
and on and on
One of the mods of the GD Board claims to have hundred of aliases.  They are not  going away.

Pauliea!!!!! OMG good to see that you are still doing the hobby thing

I hope all is well with you!
Not sure if you still get PMs, so I had to say "hello" to you here!

xoxos

Betty

How's that for an alias

sorry just kiding - it' s a joke, get it?

Just look down the page here, and at many posts on the General Board.  Alias posts have been with us a long time, and, IMO,  have reduced credibility now as is then, except where it is obvious when posting under an alias is the right thing to do.  Mostly, this is not the case now...

As for alias reviews...bullshit policy.

And hide behind your words.  If it's good enough to say, then say it with your own TER handle.

Otherwise, shut the fuck up.