I don't think this is completely true. You may not be able to adjust your thinking in the short run, but you can over time. I know this because I am old and married. If you get married and stay married for a couple of decades, you will have to adjust your expectations from a looks perspective as you age. Your spouse will do the same.

If you cannot do that and you're only attracted to people of the opposite sex that are beyond your reach, then you're doomed to loneliness. If you're in this situation, wouldn't it make sense to at least try?

"I don't see people reprimanding women for refusing to lower their standards, despite their unattractive traits."

I do. There are countless posts and articles reprimanding women who only pursue the "sixes", six foot tall, six pack and six inches....