A president elected by the parliament used to be a pretty common thing in many European countries. It's simply a different model. Keep in mind that in virtually all European countries, the office of the president is not particularly powerful. The government/parliament combo is where the power is - the president is in many countries little more than a guy/gal opening new motorways and representing the country at international summits (but foreign policy is crafted by the Secretary of Foreign Affairs equivalent).

The "election by parliament" model has been/is now being phased out in favor of direct presidential elections in many countries, but let's not pretend like we're dealing with something particularly unusual here.