Yes or no?
Yes it is
Absolutely!
If it is angled past a 90 gravity is working on it.
Hmmm interesting though that it is always angled at least 1/4 per foot right? 
Seriously though it should be 2 times the trap diameter going horizontally which if a kitchen sink would be 3" and 2 1/2" if bathroom.
That’s not an indicator of an “S” trap, Bob. The lack of a horizontal run after coming out of the trap is the problem, ie. a siphon break. A siphoning effect could be the result, causing the trap to drain. But I know that you knew that. 
Then why the Mr wizard talk?
Did you understand what I meant about it never actually being horizontal? 
Lets see some steam from those ears Jeff. ha
The real question (honest) is how far past horizontal it is allowed.
Fun fact…plumbing fittings have the 1/4 in per foot angle built in.