Like it or not. Public lands under the present adminiatration have been designated for "multiple recreation use" to include esquestrian and motorized travel whether it be for scenery or physical challenge. Not everyone wants to stop and smell the daisys and you need to get over your idea of your form of outdoor recreation as what is holy and valid.
If you have a local issue with off-roaders breaking the law, then report them. Go to the BLM, the NFS, Sheriff etc.
I realize ~you~ are not personally at fault for our own local turf battle in Washington, but I think it is symptomatic of a notable culture clash, and a personality characteristic of people who like their own engine noise more than they like the scenery they ride through. The horse people don't invade the bike side, the bikers invade the horse side when their side gets all tore up. The bikers should respect our desire for quiet on our side as much as I respect their desire to make noise on theirs.
Of course we reported slashed tires.... They said there were lots of other reports just like ours, always horse trailers. No witnesses.