Different items with the same unique active allow the use of both, unlike unique passives

(I originally posted this on the Rant board but im posting it here in case there actually is a bug)

As far as I know, the only case where this is possible is with (SR) or (TT) and When you use one of these items, you can use the other immediately after. If you got multiple stopwatches before breaking one, you can use several in the same fight. Why doesn't using one of these put the others on a cooldown? If you can't stack unique passives, shouldn't unique actives lock each other out?

Yes, it is expensive, but it is pretty powerful as I witnessed once in a ranked 3s match, the same guy used wooglets and two stopwatches one after the other, which allowed him to basically defy all odds and win the fight for his team.