The reason for this restriction is security, plain and simple. The TSA wants to make sure that no one can bring any suspicious substances on board that could potentially harm other passengers. It's like trying to prevent a recipe for disaster from being mixed up in a tiny bottle.
But what about all the exceptions to the rule? For example, medications and baby formula are allowed in larger quantities, as long as you declare them at security checkpoints. It's like having a get-out-of-jail-free card for your liquids, as long as you follow the rules.
So, how do you pack your liquids to ensure you don't get stuck at security? One tip is to use travel-sized containers that are specifically designed for carry-on bags. You can find these at most drugstores or online, and they're usually labeled as "TSA-approved".
TSA Approved Quart Size Bag Dimensions Ultimate Guide