In my town, we have many signs that explain bicycles can use the entire lane. In fact it is a state law. The law would also require that motorists give at least three feet of space to overtake a bicycle so even single file it would have been necessary for cars to cross into the other lane which is also allowed. And bicycles in Oklahoma can treat stop lights and signs as yield signs if the way is clear. IMHO, bicycle safety and advocacy should preserve the cyclist's right to ride and protect them from motorists in situations like this rather than make them haul their bikes to a MUP.
Unless these guys are using the wrong chain lube, tire pressure, wrapping their bars the wrong direction, or wearing the wrong socks, I don't think this is anything to get upset about.
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"It is the unknown around the corner that turns my wheels." -- Heinz Stücke