There's probably some regional differences in what is acceptable and what isn't. Like kissing cheeks is normal among casual friends in some countries (e.g. France) but where I am it's reserved mostly for family. Same thing with holding hands: for me that's a romantic gesture unless it's with a child, whereas hugging is normal friend behavior.

So far my therapist has made no attempt to hug me but I'm not really that big on hugs or being touched in general, so I prefer it that way.