There is absolutely no reason why a vaccinated player should have a shorter isolation time than an unvaccinated player. This is pure politics. You either have Covid and can spread it or you don't, they just want to penalize the unvaccinated.
“...they just want to penalize the unvaccinated.”
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Blatant use of the carrot and stick technique to ratchet up the pressure on players to knuckle under and agree to be jabbed.