I found out that if two finger tap itch when it is open in dock or just when it is in dock and hover over options that you can then show it in finder and then you can move it into trash and then delete it that way. I also found the itch book which helped me come to this conclusion, just go to installing on Mac and it will have instructions on how to uninstall it, but not the way I just found out through pure luck. If this helps at all, please let me know. :)
https://itch.io/docs/itch/ - Itch Book