technically speaking, yes, unless you're a parking cone.
Now my question, why isn't masturbation considered a homosexual act?
I'm sure someone, somewhere, has argued that masturbation is wrong because it's gay. Also,
this.As for why people in general don't consider it a homosexual act, well, my guess is it's because masturbation is the norm and homosexuality is not. Plus, plenty of people who are exclusively heterosexual (in sexual acts that involve more than one person) do it, which makes one wonder if it is homosexual in any meaningful sense as opposed to by technicality.