I think it would be more appropiate comparing those vessels to auxiliary cruisers. Historically there were the Raider vessels, one notably the Raider G Kormoran, which were refitted merchant vessels with boasting weaponry to pack a bunch, however as they were limited by their very design of the hull they could only do so much. Longhorn and Bulwark are similar in that regard, but they're way more frail than most people like to believe.
However, an important detail would be, that actual aux. cruisers could hide their armaments, which the vessels we have presented here can clearly not, which doesn't provide any incentive to ban them for subversion.
These vessels possess enormous hitboxes, barely sustainable power cores and have certain quirks and kinks to their gun placements. Pleading so much on the emphasis of role play consequences, but not providing a follow up of why Bristol should be exempt of using these ships feels rather like lazy gatekeeping to me. There was never any role play interaction to begin with, which would lead to such event to happen. All we were made aware of, is that these experimental craft possess some merits, with an already pre-existing safelock to not hand them out to everyone freely.
Agreeing, with Sombs here, rp is fun if both sides had fun doing it, developing a situation to happen that would justify it.
Furthermore, appreciating Tekagis response to bring a change and suggesting a new framework to approach the issue somewhat.