So how to understand the quoted sentence properly?
In answer to the question 'did I understand the quoted sentence?', yes it appears you understood it well.
Does it make sense to break it this way?
No, not at all.
Is the grammar correct?
Yes, "Drinking wine is not akin to being roofied" is technically correct.
Consensual sex is not akin to being rubbed up against in the subway.
Consensual sex is no more akin to being rubbed up against in the subway than drinking wine is to being roofied.
The sentences cannot be broken apart. Saying that "Consensual sex is not akin to being rubbed up against in the subway" is an obvious statement, of course it is not. However, that is the point that the original writer is trying to make. By using a comparative adjective, the writer is attempting to draw an analogy to something that is clearly not "akin".
So the writer could have stated:
- [being rubbed up against in the subway is no more akin to consensual sex] than [suicide is (akin) to being pushed off a roof]
The emphasis is the comparison, not the alliance of sex and molestation.
A whale is no more a fish than a horse is
This also is technically accurate but just too obvious to bother writing. The original statement is clever for the analogy. It would make better sense to write "a whale is no more a fish, than a horse is a donkey".
She is not more clever than he is
This doesn't sound right, see the link above of "no-or-not", if you take the "cleverness" to be "more clever than someone", then the appropriate negation would be "no more clever than someone". Alternatively it could be written "she is not as clever as he is".