Yes, I do assume so, since neither the authors nor Moxie himself indicate that they have had any communication. I cite people all the time without contacting them, and I have been cited without being contacted.
The paper makes that quite clear by calling him an SLL expert and referencing two of his vulnerability discoveries. Academic papers are stingy with both personal praise and references. Anyone who receives either one of those I assume is an expert in the field.
In my experience as an author and reader of such papers, they are. References take up space, and every reference you make is less of your own work that you can discuss. So I think very carefully about who I'm going to give my precious paper-space to.
Don't confuse a paper having 30+ references as being generous. If they could have supported and justified their own work with less citations, they would have.
I have somewhat different experience. I usually include more references than strictly necessary to support the work, because there's an expectation of general credit-giving: if someone else works in a related area, even if their work isn't directly on-point or needed in the specific paper at hand, it's often expected that they get a generic nod in the "related work" section, and reviewers may complain if that's not done. But often the reference amounts to little more than a friendly ack: yes, I know paper [2] exists, and I hereby acknowledge it.
My last (ok, only) published paper cited 47 other papers or books. I felt absolutely no compulsion to reduce (or, for that matter, increase) that number, nor does the number of citations have any connection to the amount of time I could discuss my own ideas ("See \textcite[p 6]{someone2005}" doesn't take much space).
It's not the citation in the paper, it's the two or three lines the reference itself takes up in the references section. When we publish papers, we are always pressed for space, and we always have to decide what we have to cut. I can't speak for where you publish, but in computer science conferences, we have page limits.
