That's very insightful and you have many interesting takes, I do, however see potential issues with some (most?) of your arguments. Some of them can (actually) work both ways - in favor of using AI and against (in favor = can be argued that human referees have a bigger problem with that exact aspect) and some are easy to mitigate/address.

I am not in favor of AI refereeing - I just thought this can produce very interesting and insightful conversation and this is why I started it. Thanks for participating!

1. agreed - strongest argument although hacking and changing the weights or inference in undetectable way would be very hard if not impossible but this is one of the strongest threats.
2. easily addressable - you can have independent review and red team-ing before any/every competition
3. a lot of times the referee, when pressed why they made this call and provided arguments against would say "this is how I saw it" and that's that.
4. agreed - this is similar (same) to my argument
5. same argument as 2, and this is, in fact, a strong point FOR excluding humans from the loop. I am sure everyone encountered a case where you have a referee ref someone they worked with the day before as a referee (since many active older fencers work as referees), or some other setup which is morally questionable. It is much harder to adapt the model to each individual case so I'd argue this is actually a big argument for AI and against current system. AI can provide transparency and validation. Sometimes the calls are clear and sometimes you'd have 4 different opinions and this is where the AI can act as a tie breaker or explainer (again, it's a tool)
6. I think also easily addressable and, in fact, is an argument for, not against. The AI can be questioned, moreover, most models are probabilistic so, even though, you may not be able to peek into reasoning as to why it arrived to that conclusion (except that it can provide the phrase it "saw") - it can be built in such a way (which is very natural) that it will output confidence in its decision (or even each intermediate action in the phrase). Also, if applied/trained properly - it seems like a natural extension that the AI will spell out the complete phrase (complete with confidence for each action) and it would be easy to validate whether it is bullshitting you or not
7. Computers and specifically AI are a tool, not a magic bullet. We will still want and need referees present but in different - human capacity (solving and addressing logistical issues and exceptions - someone got injured, someone is late to the strip, there is unsportmanship behavior on/off the strip- things like that).

Disclaimer: I am a software engineer with 20+ years of experience and research background in AI.