Just because a license says something does not mean that everybody interprets it the same way or that the clauses are valid in it. The "Remote Network Interaction" section has never made it to court and there are countless different interpretations one can draw from this.

Precondition: Take a GNU Affero GPv3 product, modify it, and expose it over a network, directly or by proxy, over a network, for users to use.

Your four possibilities:

(1) If you provide source, and the courts uphold the 'Remote Network Interaction' clause: you're fine.

(2) If you don't provide source, and the courts uphold the 'Remote Network Interaction' clause: you're screwed.

(3) If you provide source, and the courts don't uphold the 'Remote Network Interaction' clause: you're fine, but you would've been fine not providing the code in retrospect.

(4) If you don't provide source, and the courts don't uphold the 'Remote Network Interaction' clause: you've defeated the GNU Affero GPLv3 in court.

You can absolutely make the argument for or against the business risks of releasing source code, but you can't make the argument for 'uncertainty'.

If I take some caching algorithm from RethinkDB and put it in my fork of OpenSSL, do I have to make it possible for everyone who connects to my SSL server to download the source of my fork? Do I need to start stuffing the URL of corresponding source into my certificate?

I'd hope the answer is no, but what in the license makes it clear that the answer is no?

As the AGPL hasn't been tested in court, we're all mostly guessing.