Because China, Russia, and North Korea run psyops that either directly or indirectly harm western nations, such as by endorsing, and in some cases funding and arming, people who oppose or disadvantage the governments and peoples in those nations in any way and by doing anything in their power to decrease credibility and trust of those nation's governments.

Examples: China used its TikTok military op not only to collect and categorize americans (and other nations) but to directly endorse Donald Trump for president, followed by the largest shift rightward in young voters ever recorded. China wants Anarchy in the west, China wants an opportunity to grow their own borders unchecked and become the dominant global superpower.

If you're a Tankie

You support Russia, China, and The Dictatorship of North Korea.

That's like the definition of the word.