Tell the teacher if...
Tell your teacher:
If you have relatives in Russia.
If your parents speak Russian at home.
If your parents watch TV in Russian.
If your parents talk badly about Vladimir Zelensky.
And you are surprised? They want to identify any potential pro-Russian parents and investigate them.
Russia invaded Ukraine and killed, and tortured Ukrainians en masse.
Pro-Russian support is probably considered a national security threat. I am not surprised. All other EU countries should do the same.