A thinsplainer will tell you about all the woes of being skinny that we already know and
sympathize with, only to invalidate your problems. They are
naturally skinny people who start quacking about it only when anyone heavier talks about their problems. Similar to men who only bring up men's problems to invalidate women's problems.
This is so that they too. can have the joy of taking part in the
oppression Olympics, since they often get left out, due to conforming to society's standards of beauty.
After whining about how oppressed they are, they go back to eating whatever they want and not gaining a pound. Usually a woman.