I was told that it's not exactly the case and copyright laws in Russia are pretty severe (just rarely enforced) and by laws there may be copyright infringements on those fonts (by low no actions from Microsoft are required to protect their intellectual rights)

Ah... interesting, a bit of GPT-research tells me that in Russia font shapes can by copyrighted, but no so in the United States, which I had assumed was the common rule world-wide.

The key points are that this was a lawsuit by a rival candidate, not Microsoft, and was overturned by a court of appeals because it was without merit: the candidate Mikhail Matveyev used the Arial and Tahoma fonts in a report linked from his campaign website, which the court deemed not to be part of his campaign materials. Not to mention that having a license for either Office or Windows will give grant the rights to use those two fonts!

In other words a rival tried and failed to get him on an invalid technicality.