This is another example of a salesperson just making stuff up. If Chrysler didn't think it was safe for that seat to hold a child seat, there would be warnings all over it and they certainly wouldn't have gone through the trouble of adding LATCH to it, which has no purpose other than to do that very thing.
Thank you generaltso! It makes a lot of sense and that's why I'm looking this up. Weird too that 2 different sales people at different dealers had the same story.