Well, but in that case it actually made at least some sense. There were disasters and crimes happening because magic gates appeared everywhere- so naturally, the space sheriffs suspected magic users- of course it was a bit random to just mention Haruto and Nitoh, but other Sheriffs might have been after other mages too.
Gavan stopped attacking Wizard, because he trusted him- they kinda worked together after GokaiSilver joined them. Sharivan, on the other hand, didn't know Haruto or Nitoh and still suspected them, which is why he kept attacking them.