Finland joining NATO would really make you a colony...of the US. You would be required to buy US weapons, host US troops, have US military camps. Instead of being neutral in the eyes of Russia, you would have taken a direct stance with a military alliance that (nearly) openly states their reason for existance is to destroy Russia. Congratulations!

Bonus: If the US decides to put a shitton of missiles pointed at Moscow in your country, you - like Ukraine - will have the honor of dying for US weapon maker's profits! Down to the last Finn! We'll all wear little Finnish lapel pin flags while you die!

Then if