X accused of giving racists ‘impunity’ after refusing to bar N- and P-word posts
(www.theguardian.com)
Yeah "fag" is fine in context such as: "I'm just nipping out for a fag" "Can I bum a fag?"
But you can't say it to, or about, a person, well, unless you're a homophobe.
'faggot' is almost always a slur though, you'd better be in that rare circumstance where you're very clearly referring to a bundle of sticks otherwise, no.
I guess 'nip' is also occasionally a racist slur for Japanese, but normally quite innocent; just something quick. or a pinch, or a wee dram.
Vaguely related, you might be interested in https://en.wikipedia.org/wiki/Polari. A few British slang terms migrated out of queer-creoles into more mainstream usage , possibly via popular radio and tv.