Are molds dangerous to health if they are not in my own apartment?
Most molds are harmless, or are at most an allergen. There are a fairly small number which are toxic to one degree or another.

So a lot of the fear you see is overreaction, or is folks with serious allergies. If you aren't allergic, and don't have reason to suspect that this is one of the nasty ones, it's mostly an eyesore.

The real problem is that, once established, mold can be very hard to get rid of short of ripping out any material it has grown into. A bit of dampness and old spores can bounce right back.