pants and they

Look at this sentence and tell me why use a pronoun "they" (as it should) when referring to pants.

I like your new pants. They look great.

(Here, you and I know there is only one article of clothing - pants, and why is it logical and "you and me" congruent in the world of English?

from

Strange but true.

Trousers and pants are referred to as plurals - a pair of trousers, a pair of pants, and never a trouser(s) or a pant(s).

So 'they' 'them' etc are always used.

"I need some clean pants. Pass them over to me please."

"Great trousers.Where did you get them".

There are a few explanations floating around, none of them sound very likrly to

There are a few explanations floating around, none of them sound very likrly to me, usually based on the existance of two trouser legs and historical clothing! (You don't call a shirt in plural even though it has two arms, do you?) But it is the case with trousers and pants - whether pants is being used for underwear (UK) or trousers (US).

Perhaps it's because the majority

I think 'glasses' follow the same rule. If that has a rule!

I need to buy a new pair of glasses, but nowadays they are so expensive!

( I think it's pluralia tantum)