I could answer by mentioning lack of democratic process and about self-proliferating structures of power that held him, as well as atrocities of GULAG (and the point wasn't the sentence duration, but conditions in the camps), but that misses my core point.

The point is - endless praising of Stalin as some sort of superhero is basically a prerequisite for personality cult - something that Lenin has openly warned us from (and ironically got an even bigger cult himself).

Stalin is a leader, and in many ways, an excellent one. But turning him into a flawless genius of socialism and barking at any attempt to mention any flaws in his policies doesn't promote a healthy discussion and turns otherwise reasonable left movement into a self-contained cult.

I suggest we all agree Stalin was no superhero and no villain, he just did what he did. He allowed for the insane levels of industrialization and has shown himself as a strong leader during the WWII, but he also held authoritarian grip on power, held political and other prisoners in inhumane conditions, and was the one to make LGBT illegal in the USSR.

Stop glorifying or demonizing him, that's all I'm saying. The rest is true.

There's no point trying to explain political concepts to those who don't wanna hear. You're wasting time and resources that could be better spent elsewhere. Let her have it.