/ Why are Polish so conservative and religious?
I think you can find many parallels between the Polish and Isreali nation and diaspora: the CBOS opinion poll ranked Isreal very closely to Poland in its religiosity, and Isreal has a thriving, intelligent secular class (they go hand in hand). Of course Isreal has it's Zionists as Poland has its die-hard Mafia-Catholics, and both exert a disproportionate hold over political power in both countries.
If you look at the two countries' tragic histories, their monolithic culture and nation-state, you will find many similarities and possibly an answer as to why Poland chooses group together under Catholic's veil.
I think GabiDaHun hit on two important points:
1) The Catholic church was the only uncensored voice against communism for nearly 50 years.
2) The Pope during this time was Polish.
But that's not the only reason why Poles hold onto their imaginary friend. When a country goes through what Poland (or Isreal) went through, you band together under any cultural affinity. Unfortunately, that affinity happens to be a religious one in Poland. Majority of Poles themselves aren't as extreme in their views as the Fascist-Roman Catholics-- in Poland, women enjoy equal rights; the majority of Poles believe in contraception and condoms (I think many Poles cringed when Benedict went to the worlds most AIDS infested continent and told the people there that condoms don't work); and, above all, Poles believe in education, math, and Science. Science. Science. Science.
So I think the question that is being asked is why there's such a disparity between Polish values and their religion. The answer: cultural history.
And soon, once Poles drop the shackles of religious dogma, it will all be history.