Is it bad for a MacBook to be too cold due to AC?

User @xWauwau is correct in their guidance on temperature.

Your computer won't be damaged by the room temperatures maintained by your home AC unless you maintain an extremely uncomfortably low temperature. 🥶

This from Apple on the subject: Keep your Mac laptop within acceptable operating temperatures - Apple Support

The risk is not for low temperatures, as long as they are not so low you are also VERY uncomfortable.

The risk is moving a COLD MacBook into a warmer or more Humid environment, and drawing warm moist air into the unit without first letting its temperature acclimate.

This can cause condensation on the cold metal surfaces, and condensation can be damaging.

I keep my MacBook Pro cool in the summer the same as you.

The first summer after purchase, I had the air conditioning on throughout summer.

Your machine will generate heat while running, so keeping it cool is good. 😎

Good luck! 👋🏼😉

NOTE: The Lithium Ion battery inside of your machine is flammable and explosive.

It is best to keep it at room temperature.

Inside of every Apple Retail Store is air conditioned to keep cool, not freezing.

MacBooks should not be used or kept in areas colder than 10° Celsius, or 50° Fahrenheit, as the battery and other inner components could sustain damage.