Guy is biking on an apparently busy road at night in dark clothing and no rear light, which is legal but stupid. Guy starts interchange with cop by going on about his 5th Amendment rights, acting in a highly agitated state, and explains his agitation to the cop by saying he's in a hurry. Cop quickly does the warrant check, checks the law, and tells him he's not writing a ticket, tells him he's free to go. Guy then tries to debate the cop and even tried to insist that a ticket be written. Guy drags out the stop for several minutes.
Cop didn't have to assume anything about night cycling , this guy was sending all sort of dangerous low life signals. After saying he was in a hurry, he prolongs the stop to engage in a roadside debate.
Jackass.