Indeed, you can't do this immediately but the saying "you can't double spent" leads newbies to fear/feeling scammed/posting aggressively in the tech forum.
I agree with the sentiment (too much FUD spread around in general) but at the same time it should be understood that the entire *premise* of Bitcoin was to "solve the double spending problem" (so IMO not really a useful thing to tell people that you "can double spend" as it then leads people to infer that Bitcoin is *fundamentally flawed* which is isn't).