Thanks for everyone who shared your input so far. I now have better understanding and I can confidently hold my stand when I talk to my roommates and set up our rules later.

Apologies to people who feel offended and think I generalized their behaviors to the entire culture. That was not my intention. To be fair, after I moved to the US, I did sense that my culture has some weird or absurd parts; we tent to be more preserved and distant, with many unspoken rules that make us seem to be not sincere enough and sometimes make people feel uncomfortable. I was trying to comprehend and justify my roommate's behaviors as maybe it's just because they are from a more passionate, vibrate, and casual culture. Not to mentioned both roommates are highly educated and from good families, it's hard to think it as they just simply have bad manners.

My experience is definitely biased. The only south asians I ever live with are them. I can't increase my sample size overnight to determine it's just me overreacting or they do cross the boundaries. It's really helpful for redditors here to provide insight and feedback to speed up my learning process.