after St. Louis police unions instructed officers to publicly display The Punisher's insignia (the mark of a lawless, fascist murderer) the comic book community was quick to point out the stupidity, and the frankly horrifying message sent by supposed peace officers endorsing a maniac. So it's a good thing The Punisher personally confirms he hates cops who see him as a friend… making every cop who "wears his mark" or calls themselves a "fan" look like shameful fool in the process.
-- Andrew Dyce, The Punisher Confirms: He HATES Cops Who Support Him
Even captain america does plenty of fascist things mate, Punisher is definitely very close to fascism by the mere fact that he represents someone who thinks they are above the law and they know better and that they can deliver their version of justice.
Of course that alone doesn't make him fascist, but the things superheroes are portrayed doing nowadays are very much things fascists like.
Id recommend checking out this excellent video from Folding Ideas for example
https://youtu.be/xLUvR8zKbh0?si=H-cHenS9AfuXbJiW