Totally agree, his previous support for the Russian invasion doesn't make him more guilty of cheating.
However just for that he totally deserves to get all the hate he's getting. I don't understand how this player is still allowed to compete. Should have gotten a lifetime ban from all event organizers imo.
As you already mentioned, by going echo saber in favor of BF, you're sacrificing a lot of farming ability.
I guess harpoon can be good in some scenarios (like you already mentioned, getting kited by slows/stuns), but I'd ask myself if harpoon is really better in this scenarios than other popular items such as BKB or Manta.
Personally I think harpoon is super niche on juggernaut and if anything I'd get it as like a 3rd or 4th item. Definetly don't skip BF for it.
I was wondering about something similar, like setting up a VM for it. Doesn't really fulfill the "always on" thingy, but regarding malware etc. this should be safe, no?