Your non-expert may have a point, sort of.
In addition to the point raised by tt2, which could well be the real cause of the problem, the most obvious issue with using an iPod Classic in the car is that the movement of the car may (will) cause the hard drive (in the iPod) to have to work very hard to keep up the flow of music.
In other words, the movement of the car causes the read head in the iPod to lose its place every time there's a bump in the road and it then needs to catch up, or find its place, before it's needed. Imagine that the read head is reading the music ten seconds ahead of playing it to you. If the iPod suffers a bump that causes the read head to lose its place, it has only ten seconds to find that place again. If it succeeds, you don't notice, but if it fails to find its place in time, there will be nothing for it to play to you, until it does catch up. Hence, a gap in playing music, which possibly, you're interpreting as the iPod freezing up.
So while the Classic can tolerate a certain amount of movement, excessive bumping and movement can mean that the read head cannot recover quickly enough, which results in gaps in the music being played.
If you have a big car, with very soft suspension, the iPod may manage, but if you have a small car, with a firm ride, the iPod will struggle to cope.
By comparison, the iPod Touch stores the information on solid-state memory - in other words, there are no moving parts to be knocked about, which means it can deal with bumpy cars without problems. (It is still a delicate device, so no chucking it across the room or dropping it on concrete!)
So to expand on the non-expert's opinion, if your current iPod connects to your car by either the dock connector to USB port in the car, or by a lead from the iPod's headphone jack to the car's AUX input, you can do that with the modern iPod Touch. (By comparison, the modern iPhone does not have a headphone jack, so cannot connect to the AUX socket in a car). If your car does not have a USB socket, the modern iPod Touch cannot use that method.
Today, on modern cars, it's possible to connect an iPod Touch (or iPhone) to a car's stereo by Bluetooth, but if your car doesn't have Bluetooth, that option is also not available to you.
So at a guess, your non-expert has simply given a brief explanation of what I've said.