Sanchez was absent from Arsenal’s season-opener against Leicester with an injury and sat in the stands as they came from behind to win 4-3.
And the Chile star wants to quit the Emirates altogether for Manchester City.
Arsene Wenger has refused to sell despite there only being 12 months left on his contract and he looks likely to leave for free next summer.
And Collymore thinks his attitude is shameful, also tarring Danny Rose with the same brush.
“Some Arsenal supporters seem happy to say, ‘Alexis Sanchez is a great guy, he’s a model pro’ but I am sorry, he is not,’” he wrote in his Sunday People column
“He is angling to get out of Arsenal and he is not doing it in a proper way.
“Like Danny Rose, he is a disgrace as well.”
Rose spoke out publicly about Tottenham’s wage structure and transfer policy but has since apologised for his comments.
He did say however that he wasn’t trying to leave the club this summer.
But Sanchez wants out of Arsenal ASAP after they failed to qualify for the Champions League and Man City and PSG expressed interest.
Sanchez is now in limbo and looks set to see out his contract with Arsenal refusing to sell to a rival despite City being willing to spend £50m.