Maybe it is all fun and games, but they don’t write about that stuff on their blogs so it’s impossible to tell. From my point of view Gruber’s reply doesn’t read as friendly or jocular. Lyons calls Gruber a egotistical, obnoxious fanboy and jokes that Apple hatched a wide-reaching conspiracy just to trick him into a journalistic mistake. Fair enough.
Gruber “jokes” that Lyons writes limp, insincere, watered-down articles for a failing magazine. Maybe Gruber misjudged his tone, but ouch. I’d be hurt if Gruber wrote that about me. I’d be hurt if a _friend_ wrote that about me.
They don't have to be drinking buddies for this to be a sincere form of flattery.