Poland very much is part of the West, and is actually on course to become one of the richest countries in Europe over the next twenty years as measured by GDP per capita.
Over that same period Europe is projected to become poorer than Asia in gdp ppp for the first time in 500 years. I'm sure I won't be hearing Poles making the case they are actually part of Asia within those 20 years.
The whole west/east dichotomy is an artifact of the Cold War. Countries aligned with the US and Europe are "west", countries aligned with the Soviets (now Russia) are "east".
Nowadays China is taking the helm of "east" from Russia, but either way it's a geopolitical concept and remnant.
