Many nice guys, if they are in fact good guys, are simply the male equivalent to an attractive female. A woman may not always feel attracted to a specific guy, but often times they are still of equal socioeconomic class and status, and may be very similar individuals with similar upbringings and lives.
As men, we're only attracted to what is normal to us. How are our standards "too high?"
when looking for a partner I look at every aspect of them and go with someone I am attracted to, like, and have chemistry with. if someone doesn't suit my standards in a partner (but seems interested in me or tries pursuing me), it does not mean I feel they are shooting for someone out of their league or that they have too high of standards. people like what they like and want what they want. I don't see people as out of my league or below me, I see friend material vs. dating material. simple as that.