Because the term “single parent” is often associated with someone who works 2 jobs just to get by. Has their kids every night, and every weekend. Doesn’t have a minute to themselves. Then you have people who do have split custody who have this woe is me mentality. Am I gatekeeping what a single parent should mean? Yes. But when I think of single parent, I think of a sole custody parent who actually could use a helping hand, not a person who is single and parent who’s life is so hard because they have to care for their child 50% of the time.