The so-called invasion affected about 250,000 people (correct me if I'm mistaken) and was not an invasion of Czechoslovakia which would include the whole country. Many Poles and those who thought of themselves as Poles in that area did not think of it as an invasion but as a liberation (back) to the homeland. In ironic fashion it could also be considered a defensive move to the overall military politics occurring during these frightful years of German buildup.
There can be no other words - Poland invaded Czechoslovakia and kicked her hard in the face when the country was on its knees. Worth pointing out that most of those people didn't see themselves as Czech or Polish, but rather they identified with the local area. Still common, even today there.
The link is sadly biased - I quote -
At that time, Zaolzie, covering two thirds of the western part of the Duchy, had a clear Polish majority, a fact recognized in the agreement concluded by local Polish and Czech councils to divide the area into Polish and Czech administrative regions. The Czechoslovak government, however, did not recognize the local agreement; it claimed Zaolzie as part of the historic lands of the Bohemian Crown. It also claimed that Czechoslovakia needed the region's Karvina coal mines, which provided high-grade coking coal for the steel and engineering industries of the region, as well as the town of Cieszyn because it was the key railway junction between Bohemia and Slovakia.
Cieszyn was not the important rail junction - Bohumin is. It's also worth pointing out that there wasn't a clear Polish majority at all - these people identified with the local area, not the national cause (whatever it was).
Pi³sudski sent a special delegation to Prague to negotiate an agreement with the Czechoslovak government in December 1918, but the delegates found it unwilling to do so. In early 1919, just before elections to the Polish parliament, and while most Polish troops were fighting the Ukrainians over Eastern Galicia and resisting the Red Army elsewhere, Czech troops moved into the region and, after some bloodshed, took it over.
Oh dear. The article completely glosses over the reality - that Czechoslovakia sent the troops in because Poland was breaking the interim agreement not to establish any national structures there.
That's only a small aspect of what is a terribly biased, nationalistic piece of work.
Ah yes, one of the most favorite subjects of Polonophobes :))) Punks forget that the whole thing happened already after the Munich and that part of that area was going to be taken over by the 3rd Reich. So much for cooperation with that mysterious nationa called Nazis :)))
Better to let it be taken by the 3rd Reich and to have the moral upper hand than do anything to be associated with them.
For all the preaching about being the Christ of Nations, interbellum Poland was anything but.