What is the issue of Muslims and dress code? I know arabic isnt always necary & u jst hav 2 dress modestly?

Well, muslim men dress like arabs cause that is what Prophet (pbuh) use to wear.. it is a Sunnah "Way of the prophet" to do what he does because we muslims belive we will be rewarded greatly if we follow Sunnah. No it is not nessecary to wear that in the mosque .. in the mosque it applies that you should wear anything as long as it doesnt "expose" alot, And Many muslims wear that even if they are not praying is because they are following the Prophet (pbuh) and his ways. Hope that clears it out for you.