People keep forgetting your starting companions are lawful evil vampire, lawful evil cleric who worships Shar, "alien" who is super xenophobic and her race is known to raid and pillage most of the time when they are not hunting the illithid so no wonder they are rude, mean and cold to you what I like is how they behave like real people would no longer from super meanie to super nice guy because you got the exact amount of points in their approval you can make them friendlier to you by accepting them and showing them a place where they can stay because your entire camp is full of outcasts. People like Gale and Wyll are way friendlier and nicer because these are good characters so I find funny how people were complaining about your companions being harsh to you.
That's like bitching about Viconia being super edgy, cold bitch who never smile and shadowheart is a big hand for Viconia from the first game as both are evil clerics worshipping Shar, so why no one complained about Viconia, yet everyone has a problem that shadowheart is mean lol. I would love to get more variations for companions and add missing core classes (Barbarian, Druid, Monk, Paladin, Sorcerer, and Bard maybe Artificer?) and maybe more subraces for each race dark dwarf, ghostwise halfling etc.
(With the disclaimer that I don't have my own crystallized opinions on companions yet.)
You're conflating "evil" with "unlikeable", "annoying", "bitchy" and a couple of other things that don't need to go together. From what I can tell from reading this forum, it's the latter that many people don't like: companions criticizing every small thing you do and generally being a pain. No one complained about Viconia, because Viconia may have been a cold bitch, but wasn't bitchy.
BG2 is actually a good example of evil characters being "likeable" (the whole evil cast I think) and good characters being "unlikeable" (YMMV, but let's say Nalia, Anomen and Aerie.)
So the problem isn't generally the morality (or lack thereof), it's how the characters are portrayed; their personality, their writing. On the subject of the latter, several users noted that they all behave like characters in a teenage drama or the like. It's not just evil alignment. (Wyll and Gale have also been criticized.)
But it's also not that I don't see your point: some people ARE complaining because the evil companions aren't instantly chummy with their PC. And since most people tend towards "goody-two-shoes", it's more likely the evil characters won't be happy with how things go.