It’s ridiculous to you. It’s not ridiculous to many. Especially when COMs and relics come with so many combinations of skills and passives. I could easily have 3 mules for one single class mod type. You only said weapons btw, don’t forget shields, coms, artifacts, grenades… And i use way more than 4 or 5 different guns. There are so many part differences too. Idk how many Stagecoaches i have that are basically completely different.
You are greatly underestimating the power of wanting a perfect build with perfect part weapons, perfect annointments, passives, skills… I have probably 40 mules and I’ve gotten rid of a few things i wish i hadn’t already just because i’ve been lazy.