I really shouldn't have to take the time to explain, but the parent comment was poorly written.
If Trump had a couple ounces of pot he'd have been in jail this whole time.
What you actually meant (according to your follow-up) was that if it had been someone poor with a couple ounces of pot, that person would have been in jail this whole time. But you wrote Trump, and then someone logically thought, "No, Trump would get away with that too."
The fediverse would be better if i) commenters were a bit more careful with their wording or ii) they didn't pounce on people rudely for misunderstanding them.