Of course you are not cruel! What ever gives you the most control over your dog should be commended!
I really would ignore this woman. I can see both sides though. I have seen dogs do great damage to their necks because they lunged while on a halti - and had their necks jerked back. But then again I know people who's dogs lives were enriched dramatically because they were able to take their dog everywhere without pulling!
I use a choke chain on Tilly. Am I cruel?
She walks without any pulling. Could it damage her? Yes. Do I use it correctly? Yes.
It is totally personal preference as to what you use with
your dog. Whatever works best for you and whatever you use correctly!
Nothing will be right for everyone
Goodluck with the training - you'll crack it eventually!
