Yeah I also found that very odd. Officers kitted out with riot helmets pushing bike cops into protestors. Even if they had all been riot police, it seems like a terrible, half-hearted tactic?
I'd guess the bike cops are there because they can hold bikes in front of them, which makes it just that little bit harder to advance over them?
A diversionary tactic. Its mostly white males so they're bound to pause, come over, kick the tyres, want to pick up an weigh 'em, possibly get into some componentry chat, likely forget what they were up to 5 minutes earlier.
I'd guess the bike cops are there because they can hold bikes in front of them, which makes it just that little bit harder to advance over them?