No.
Abnormal behaviour simply means that it is a behaviour practised by a minority.
Steve H is correct, you are wrong.
Wrong - virtually any definition of abnormal you choose includes a pejorative, and negative slant. So for example:
'different from what is usual or average,
especially in a way that is bad: (Cambridge Dictionary)
'Deviating from what is normal or usual,
typically in a way that is undesirable or worrying' (Oxford English Dictionary)
The neutral, non-pejorative term is uncommon, which doesn't carry any negative, pejorative connotations.
So, sorry I'm right, Steve and you are wrong.
By the way, by Steve's view being an Orthodox Christian is abnormal (I think that's what you are Humph - please correct me if I'm wrong), with only perhaps a few % of the world population being so. Would you feel comfortable with being described as abnormal Humph on that basis - I suspect you might.