Why do petrol heads think they know more about EVs than people who actually have them ?

On a Nissan Leaf thread today I confidently had someone tell me that no, I didn't pay £300 for a year's charging. It was actually £4000 according to his calculations.

Do they not think I'd know my own figures or be out by a factor or more than 10 ?

These are the people telling their mates down the pub how expensive EVs are. God help anyone listening to their absolute rubbish.