Use ur judgement. What do you think of a person who rides his bike around 2am?

So what did this person do to upset or anger you? What laws did this person break? Is this person following the laws for cycling safely at night by using lights? In other words...WTF? Are you writing a book?

What about a person that drives around in a car at 2 a.m.? Or a person on a motorcycle at 2 a.m.? Or someone out for a walk at 2 a.m.? I suppose that would offend you too.

When I see a cyclist at night I notice their lights, reflectors, reflective or brightly colored clothing, and how well they obey the rules of the road. Beyond that they could be on their way to rob a bank for all I care.

Don't have a problem with it. Is he/she going to work or coming home from work. Is this a Veteran that is using the bike to battle PTSD. It could be anything.

So, why do you want or need to pass judgement onto another's circumstances.

If I thought anything about that at all, I'd assume he's riding home from a party - or to or from a late/night shift.

What do you think of a person who watches a person ride his bike around 2am?

I would be even more concerned, alarmed and, upset if this bicycle riding, pea coat wearing individual also claimed to be Vegetarian and was later seen eating Animal Crackers.

An emergency maybe?

What's the problem with that?

The dude has no babe to score! ( maybe---) But his apparel sucks! Wear something 'sporty'! He rode the bike simply cuz he avoided the usual pollution and road ragers, what ELSE!

I don't know.

At that time there's usually not many people around.
And usually, out of those few, only a small fraction would be cyclists.
This would make the whole thing a bit unusual.
Do notice that "unusual" only mean that, and doesn't carry any hint of "good" or "bad" or "suspiscious" in it.
What would make me wonder is general behaviour.
Is the guy riding like he has a goal in mind, or is he simply pootling around?
Does he ride in a sensible manner?
Lights, reflectors, placement on road?
Does his bike look OK to be used at a point in time when help isn't readily available?
Is an army jacket a sensible choice WRT weather and temperature?
If it is, there's not much to question. Obviously he had one available, and it was fit-for-purpose. Not much to question there.
If it isn't fit-for-purpose - too hot/cold/rainy etc - then I might begin to wonder a little.