Why can't men make up their mind if they want a casual relationship or a serious relationship?

when I was looking through the profile of guys. I see a lot with both casual & serious relationship. why bother with guys like if can't make their mind about relationship. i think these men will cheat more in a relationship if they can't decide which relationship they want at all. yes age early 20 are not deciding if they want a casual relationship or serious. this why I can't very annoyed.
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+1 y
I already know what I want from a relationship. I will not men with STD This my dealbreaker.
Why can't men make up their mind if they want a casual relationship or a serious relationship?
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