I don't think fans should tell players they suck but I disagree that you can't criticise a player unless you are better.
Those guys are paid millions of dollars to perform and if you perform at a replacement level for 10m dollars (not sure what holt makes) that is not good. So I can understand why a fan or journalist that pays good dollars to see games gets frustrated.
A manager that runs a big company in the ground is also better at his job than most but is criticised.
You are always measured against your field of profession and not rec hacks.
That applies to normal jobs too. If I'm lets say a computer programmer I'm compared to other professionals of that job and not against untrained people.
Still I think it is stupid to tweet players suck or shout it in a stadium.