Heat is also (thermal) radiation. So is light, radio waves, microwaves, etc. However, the radiation from a fire or the other stuff I mentioned isn’t ionizing, so unless the heat itself does damage it won’t do cellular damage.
You also give off thermal radiation, but so does anything higher temp than absolute zero.
Did you read the subreddit, or you just don’t like this kind of humor? Because I don’t think this kinda humor is below Lemmy or anything.