You’re new to Postcrossing, therefore you probably don’t know that it has been discussed multiple times, in this forum (and in the legacy one) if users should be able to exclude certain countries from sending cards. Mostly the wish was to exclude big Postcrossing countries like Germany, because some users wanted to get more variety instead of sending 20-30% of their cards to the same country.
It has always been the conclusion and decision of the admins to not let users choose to which country they want to send, because a) it’s against the spirit of Postcrossing, and because b) it would destabilise the algorithm.
That’s why the admins can’t open this door now, even temporarily - because immediately there would be demands to do this concerning other countries too.