I haven’t read all of the responses in the thread, but I haven’t seen any from anyone who is “laughing at you” for having the phobia. I’d guess that most of us have one or two of our own; I know that I do.
I don’t consider myself to be arachnophobic, because the sight of spiders and even knowing that they’re in my house doesn’t bother me much. I still get creeped out when one of them (a big one, anyway) crawls over me. That’s more because of the surprise, I think, though I wouldn’t much care to have even a “guaranteed harmless” large spider crawling over me. (I guess I could allow it if I trusted the expert… maybe.)
But a phobia is an irrational fear. If it’s not rational to be afraid of something, and yet you are, even to the point of incapacity or panic, then that is by definition “irrational” – a phobia.
If someone laughs at you for your phobia, then they have their own problems.