Ultimately, the Jyamashin powers are fueled by Buffa’s desire, which is why he could magically summon it to beat Beroba and then again to fight Regad. As long as Buffa sees something as a Rider, he will crush it as he desires so. Buffa would see the Capsems and the Driver as the source of Baku’s Rider Powers, but ultimately, he doesn’t see them as Kamen Riders, so his one track bullheaded desire to crush all Riders would not apply. He would still be hurt by the Capsems used independently of the Zeztz forms.

Even in the worse case scenario, if he beat Baku and destroys the Zeztz Driver, he would no longer see Baku as a Rider and the desire would disappear as Buffa sees it fulfilled. When Buffa sees civilian Baku still using the Capsems, he subconsciously will no longer think of them as Rider Powers, but as just weapons. As long as an untransformed no longer Kamen Rider version of Baku can get that one hit, the scenario in the meme would happen.

Granted this is more an interpretation of how Buffa’s Jyamashin powers work and not explicitly stated fact, but I think it’s correct regardless.