It is ironic that Einstein's most creative work, the general theory of relativity, should boil down to conceptualizing space as a medium when his original premise [in special relativity] was that no such medium existed ...That is correct. The concept of the aether is universally accepted among physicists today, but they prefer to call it something else because of historical prejudices. Aether theory is one of the most accepted theories today.
The word 'ether' has extremely negative connotations in theoretical physics because of its past association with opposition to relativity. This is unfortunate because, stripped of these connotations, it rather nicely captures the way most physicists actually think about the vacuum. ... Relativity actually says nothing about the existence or nonexistence of matter pervading the universe, only that any such matter must have relativistic symmetry.
It turns out that such matter exists. About the time relativity was becoming accepted, studies of radioactivity began showing that the empty vacuum of space had spectroscopic structure similar to that of ordinary quantum solids and fluids. Subsequent studies with large particle accelerators have now led us to understand that space is more like a piece of window glass than ideal Newtonian emptiness. It is filled with 'stuff' that is normally transparent but can be made visible by hitting it sufficiently hard to knock out a part. The modern concept of the vacuum of space, confirmed every day by experiment, is a relativistic ether. But we do not call it this because it is taboo.
The confusion about aether and relativity is almost entirely due to Einstein. His first relativity paper avoided the aether, and failed to address what the discoverers of relativity said about it. Then he tried to claim that abolishing the aether was his original contribution to relativity. Years later, he denied that, and said that a gravitational aether was essential. He never expressed an opinion about the aether that is necessary for quantum mechanics, but he did not even believe in quantum mechanics. Those who idolize Einstein frequently cite his opposition to the aether as his great genius idea.
I think that physicists have decided that using the word aether is disrespectful to Einstein, and that is why they don't like it.