I've heard that from others and got a similar impression after I did well on the ASVAB (US military aptitude test) and was speaking with a recruiter. It's possibly true, but it's also possible (and a less malicious explanation) that they just know you won't be happy in the position yourself and may not perform well as a result. In hindsight, the career path I was interested in in the military would have made me very unhappy, and although I thought the program they were steering me toward was quota driven, I suspect I actually would have done better in that program and been more interested.

I had a similar experience, wherein a National Guard recruiter actually talked me out of joining the army for that reason.

I also flirted with the Navy nuke program as I was finishing up my EE degree, but decided to abort the process mid-stream. At my first job after graduating my cubemate was a former Navy electrican, stationed on a carrier. What he told me about the nukes made me happy I chose to abort.

as someone thinking about navy nukes, may i ask what was unpalatable about it?

I served in a non-nuke role on a nuclear submarine for 4 years in the late 90's. My two cents:

If you already have a college degree or are close to finishing, it's best to stay away from the military completely unless you seriously plan on making a career of it. As a civilian you'll have lots more opportunities for adventure and for making a positive impact in the world. Also avoid the trap of letting the military pay for your degreee in exchange for X years of service.

If you're thinking of joining the military prior to college as an enlisted sailor, go for it. You'll meet lots of very interesting people that you otherwise wouldn't, and you may develop some good habits that will help you later. Your personal definition of what is "hard" will probably change considerably.

But DO NOT join for more than 4 years. Any less and you'll be stuck scrubbing bilges the entire time. Any more and you'll go crazy from the lack of freedom, and your math/science knowledge will have seriously atrophied by the time you get out and continue your studies.

This brings us to the nuke program. Unless things have changed since I was in, nuclear power school requires a 6 year commitment. It's definitely not worth it. The skills aren't really that transferable and, judging from the many nuclear-trained sailors I knew, the work really can't be that difficult. Trust me, if you can get through beginning algebra, you can get through nuclear power school. Recruiters will try to flatter your ego and make you feel like a genius when you get a qualifying ASVAB score. I was told I got a perfect score on the ASVAB, and I'm more proud of the hippo I managed to color with a crayon when I was 5 years old. Quick, as fast as you can: What's 4/2? 2*3? 5-1? Next question: If a gear turns clockwise, what direction does the gear touching it turn? Congratulations! You qualify for nuclear power school!

Finally, in the likely chance that you end up serving on a nuclear carrier, you'll be working with some of the biggest dirtbags this side of humanity. Imagine sleeping in a dorm full of people who only joined the navy because they couldn't make it on the outside as drug dealers.

A common argument is that they think intelligent people will become bored with the job and eventually leave it.

It is certainly possible to be "overqualified" for many sorts of jobs for exactly this reason, but the police are the only ones that I have ever heard of that actually test candidates to weed out those "easily bored" smart people. Other companies, for some reason, get by just by excluding people with impressive resumes.

Could just be the same logic that gets used in any job search quite often of "they're overqualified for this role and so will quickly get bored and move on [and I don't have anything more suited to them]", which wouldn't be specific to the police at all.