the laws are more restrictive. their rules ban certain types of knife from being carried, full stop. mostly, as you say, double edged blades, autos and balisongs. (although I assume some historical daggers would be exempt when carried for re-encatment purposes, but I could be wrong)
while theoreticaly in the uk you could carry a dagger if you had "legaly valid reason". unless it's a collectors item, (and therefore covered by sligtly different ownership laws IRRC) there is no reason (that I can think of) to carry it. hence it is just as banned for carry outside your'e own home.
locking blade folders require a valid reason, no matter what their length, where is that a law in the US?
the length restrictions countrywide are far more restrictive than the average US ones.
even if you do follow the "under 3 inch, non locking folder" rule, a policeman can still confiscate it and arrest you should they feel that you are carrying it as a weapon. as the govt ect are portraying all knives as weapons (or so it seems) this leaves pretty much anything other than swiss army knives (not deamonised, yet) highly vunerable.
The US laws are either less restrictive, or might just break even IMO.