The answer IS because there is no alternative at present.
The Ho-Ri was added at a different stage of WT whereby rules have evolved. Outside of clear massive gaps (F-16 AJ maybe) they no longer add vehicles in this manner.
If you want it removed, why?
If it is because of the exchanged German vehicle set then no one cares since that is just out of spite, simple as that. Acting out of spite is ridiculous in this context.
The OP says they do not want that answer.
If no alternatives had been found those “hidden” vehicles would still be researchable to this day.
Fortunately Gaijin aren’t listening to these possibly biased takes and since this same topic has been discussed countless times it is pretty clear the answer HAS been given. You do not have to like the answer.
The real unfairness is THIS:
Why are not ALL nations allowed to have as many “fake” (loose term but refering to the hidden German ones that have replacements and now even more vehicles at this BR range) vehicles before gaps are filled? (eg most nations have no tech tree Heavy : totally unfair some have and some don’t , by same logic)
Why is/was Germany the only nation given a medium, a heavy, and an SPAA to fill “gaps” (I have them all, they will always exist, focus is now modern vehicles so WWII lovers will just have to accept the reality)? This is THE most unfair part of this.
One nation had them for YEARS, other nations (specifically Japan) would be less without the fake vehicles (RYs, Heavy 6, F16AJ, Ho-Ris).
Question is: with so many options as the Big 3, why try to make it worst for all the other nations?
If you are using nations in game as some pride thing to compete with other nations then best of luck. Jingoistic people are some of the worst!