Im forced to say no even if it pains me to do so.
I love manga and I use such avatars when I'm in that type of forum but outside those communities its silly to have multiple people running around with every main character in every "popular" anime so yes in that sense I would love to have them prohibited. But then again its free speech issue and for some reason, if a person really absolutely feel connected spiritually and/or emotionally and/or iconographically with an unstable, moronic and utterly devoid of rational though, type of character I have to allow accept that decision though i wont respect it, even though it makes you look like a complete retard. (This mostly pertains to the typical run of the mill moeblob/shounen/shoujo/kiddy/"popular" crap that wont pass any sort of storytelling standard)
Names and avatars are there for a reason, to make you an online avatar, not a posterboard and advertising agent of something.
The only remedy to this is age. The need to copy and emulate each other or something you like is strong in young people and mostly an unconscious act.
Only with age will you learn how it makes you look childishly naive and lacking in creativity and selfworth.
Oblique references is the way to go if you want to to support something away from its own community and references, anything else is just pointless advertising spam.