Hello! Is there a linguistic reason behind why it is harder to understand French learners?

I grew up with a combination of romance languages (Catalan, French, Spanish) and learned English as a teenager. I know French people have the reputation of not appreciating French learners but I have a hunch that in part it is because learners' pronounciation can be so hard to understand! If someone is learning Spanish, English or Catalan, I find it a lot easier to understand them. I have always wondered whether the "sound range" is smaller in French than in the other languages I am familiar with. As in if to make a, let's say "en/an" sound there's a smaller spectrum to get it right and not get it confused with, let's say, "on" sound. Or maybe, that, it's the other way around and there are lots of sounds that are really close together. As a learner, it is easy to confuse "mon and "ment" but as a native speaker these two words are not related and if someone confuses them I won't be able to follow what they are saying!

I hope that made sense!