[Idiom] a glorified holding pen

[englishhobby]

What does the idiom in bold mean? Is it widely used in the USA and UK?

This place is a glorified holding pen.

Here's the context (the kids are talking about middle school):

It's where adults put you as you make that awkward transition between child and teenager so they don't even have to look at you.

 

[teechar]

A holding pen is an enclosed space where animals are sometimes kept.
Thus, "glorified holding pen" is a sarcastic figurative expression the author is using to describe middle school. It's not a standard idiom.

 

[Skrej]

More specifically animals are gathered in a holding pen so they can easily be loaded for processing of some sort - transportation, selling, working ( a collective term referring to branding, castration, medicating, tagging, docking, etc.), or collection. They're usually packed in very tightly as well to help restrict movement.

Typically what follows after being in a holding pen doesn't bode well for the animals. The best they can hope for is just transportation to a new pasture, but it's usually a harbinger of pain or death.

The usage of 'glorified' makes it far less common. You'll hear 'holding pen' much more in rural settings than urban ones of course,where it's no longer an idiom but a literal expression.