What does trigger that (which you somehow elided from your quote) is modifying the source. I must accept the license in order to modify the code as stated in section 9.

Having accepted the license I have a responsibility to offer the changes to all "users" interacting with it remotely. Very unfortunately, they don't provide a definition of "user". This may be intentional, though. There are legal definitions of the word "user" and it may not be possible/desirable to try to override the term in the license.

IANAL but in my experience, people who gain unauthorized access to software are not defined as a "user". I can't enter into a contract with an entity of whom I am unaware. There is a crucial difference between inviting people (even random people) to use the software and having a system that just happens to be accessible. There is a huge amount of case law on the topic, so if you are really curious I'm sure any lawyer can give you good advice.