Roleplay whatever you feel like tbh.
Thats the magic of a RPG. You can be a bipolar schizo murder hobo!
The problem is that the ONLY way to be evil in this RPG is to be a bipolar schizo murder hobo. Murdering for no reason whatsoever.
Baldurs Gate is much better than Fallout 3 in this respect. Instead of a LOGICAL desire to side with the Enclave, there was an opportunity to just kill everyone without any sense. It's zero freedom
I hope the developers will listen to us, and this will not happen in Baldurs Gate. The potential for an evil role is very large, we just need to be heard - we want such content, and we want it to be no less developed and justified than the good side (not to the detriment of good, almost everyone will play the game many times to make all possible decisions)
Well, there are also more neutral options, where what is "good" and what is "evil" the player decides for himself