What is the justification for them?
Why are they being added when they make the network less efficient?
Either you have an unusual manner of phrasing things, or you don't quite understand the situation.
Embedding non-transactional data has always been possible. It makes no difference whether people argue about justification. It's just something that's possible. The main reason it has become popular to do now is because people have monetised it. They've managed to convince idiots that silly images are somehow an asset class, so that has created a financial incentive to embed silly images.
It was always possible, but there wasn't previously much in the way of incentive to pay the cost of embedding an image. Now there is. Ignorant people are blaming the code. What you need to blame is the scammers who convince people that silly images are an asset class. They are the ones who have created a fake economy. And they've done the exact same thing on other blockchains which notably don't have the code ignorant people are mistakenly blaming. DOGE, for example, doesn't have Taproot, but silly images exist on that blockchain too.
I can't tell if this is a deliberate disinformation campaign or not, but I keep seeing the same names spreading the same nonsense. It does not go unnoticed.
If I understand your response, you are saying that it was always possible to store ordinals on-chain? You are telling me that this is an exploit that is increasing fees? Is it a bug in the original code that could be fixed?