I agree that this was rude and inconsiderate - I appreciate that you may not be able to move furniture etc. into an apartment without using a ramp, but it would have been better had tey let neighbours know, and removed the ramp whn it wasn't in use.
I think you would have been fine saying something at the time.
That said, it sounds as though the incidents were all related to their moving in, so I personally would prbably leave it to see whether there are any problems once they are living there, and then let the land lord know.
It might also be worth while asking the landlord about providing guidelines to any new tenants so that this isn't repeated next time anyone moves in.