I don't condone findmypast.ie's lack of clarity. In my opinion, if you remove the free collections (the ones from the National Archives of Ireland) what's left on findmypast.ie isn't worth anywhere near the annual €114 charge for the Ireland collection.
So yes, there's 'a contradiction' with this weekend's free access. A better description is 'a deceipt'. Findmypast.ie is offering free access to records that are already free to view elsewhere, and that are always free to access on its site.
Ancestry also offers free access to records that are already free to view elsewhere, but it clearly presents them as free. So no deceipt.
As to this weekend's 'free' access on findmypast, the offer is not just for the ie site. The uk, us and australia sites are also allowing free access to their bmds and census records. as far as I know, those records are not free elsewhere, so it's a valid offer for the other territories.