Unfortunately, for the ultra orthodox, yes. The parliamentary system is a majority coalition, and more often than not, the ultra orthodox parties are the kingmakers, so they get a lot more influence than one would expect.
Specifically, they are exempt from the standard Israeli STEM + foreign language curriculum (which is quite comprehensive - to graduate highschool, you need passing grades in standardized tests that includes -- among other things -- English, Math, at least one of biology/physics/chemistry, literature, history, Hebrew, sometimes bible studies -- depends on the government at the time). You have to have 20 credits among these - at least 3 in English, at least 3 in Math, and there are more requirements).
About 10 years ago, there was a government they were not part of, and this exemption was removed ; but the following cycle, they were kingmakers again and it got reinstated.
Edit: Added some details about the Israeli curriculum.
