I don't know much about ENT to agree or disagree with this, but I can tell you this is the first time I'm hearing such thing. I would be curious to hear more about why he said that.
Taking a step back,
more than half of the matriculating medical students change their mind about specialty choice. The specialty with highest "staying power" was cited as ortho (53.6%) and peds (37.7%) which means less than a third of students will end up staying with ENT or whatever other specialty. With that in mind, if I were choosing medical school to attend, specialty in mind wouldn't fall high on the list of factors to consider.