Men who are r-selected encounter exclusively horrible r-selected women. These toxic women will destroy anyone they get into a romantic relationship with. Not dating such women is a smart move. Unlike K-selected men, who have access to K-selected women, the r-seleced man has no other romantic options.
Beta r-selected men wanting to avoid the pain and suffering of dating r-selected women are going their own way, giving up on dating, marriage and children. This might be a valid survival strategy for these men.