I am pretty much the same online and in real life. I'm usually even tempered and tolerant but I can certainly be sharp if I think the situation warrants it.
Yesterday, for instance, a friend of mine (64) almost tripped
She's a very big lady and walks with a stick. Several people went towards her to assist as she said, 'I really don't want to fall, I find it so hard to get up.'
One guy (I confess, I don't like him) said, 'It'd take a crane to get you up!' laughing as if this is a joke.
I snapped at him, 'Don't be so bloody rude!' and the whole room fell silent.
I know those present would have preferred me to keep my big trap shut but even had she been a complete stranger, I would have defended agains such rudeness.