No, that's not totally reasonable and expected. Change of control can be a valid reason for breaking open a previous arrangement, especially when that change of control negates the exact reason why people would join this to begin with.

After all, if your data can be transferred at will to another entity due to a change of ownership and the agreement you made can then be annulled (because the new owners don't care about your privacy as much as the previous ones) then that's an end-run around the whole principle.