Thank you Ron for bringing this up.
I used this name when I first joined AnswerBank and when the site had a better class of member than it seems to have today.
In those early days I thought that being rather senior to the majority I would be light heartedly and affectionately treated as just another 'old git' airing his views, just as the TV show Grumpy Old Men.
But It seems now, that some just take the opportunity to shorten it down to old-git and to use it aggressively, in it's derogative term of use, take some of these replies to your question.
When I receive some answers it makes me wonder if some talk to their Fathers, Grandfathers or even their great grandfathers in such a way?