This statement is not right.
Look here Fehervary. That is a matter of opinion. You do realize that in such matters legal, juris and rights or whatnot is mostly a political issue with different people/sides having different views and standing on issues.
In this particular case the issue is murky at best and no nearly a clearly cut as you imply.
I'm honestly surprised that such a small territories would even be worthy to rise it as an issue. There is no Hungarian minority there and never has been - so what gives?
First you would have to regain Slovakia - which is at the present is not a very likely.
Second those territories are inhabited with people who own properties there.
Third I don't know exactly the way of the land there but it could be that for strategically reason those territories are important to Poland's interest.
Fourth - you are talking about pre-war border - you're awe that those territories where exchanged not given to Poland.
Meaning there are few conditions that need to be met first:
1,Hungary in a permanent position of Slovakia.
2, Territories exchanged.
3. An ample compensation paid - that could be a quite a sum.
Summary - by the time you fulfil the first condition you might find that you cannot be bothered to go into all those trouble and expenses just because some Hungarian pouring over historical maps has an OCD.
You make no sense dawg! No politically, not strategically. Unless we're talking about huge oil or gold deposits.