Bollocks!! Girls make out all the time and they're not Lesbians, it isn't necessarily sexual to kiss someone, even if it's a passionate cuz, it's like hugging with ur lips! LOL

Some guys who make out with guys are probably homo or bi, but I'm sure some (probably few) are just open-minded and having fun. Once you get into straight guys jackin' off together or having sex, then ur definitely homo or bi.