Are you seriously asking this ??
The one can, of course, lead to the other !!!
Take the extreme examples of Left-wing totalitarian regimes. The more ruthlessly dictatorial the leader, the greater the insistence upon thinking and speaking as the Almighty State requires of you.
STALIN, for example: as Left wing as can be imagined, you dared not speak up in an un-approved of fashion, on HIS watch !!
So tell me, if you can, that people he wielded power over, didn't die IN THEIR MILLIONS ....
Today, we have a more 'creeping' version of political correctness. Speak up against Muslims .. and PC imperatives insist that the act is 'racist' (... even though Islam isn't even a race !!). Tag Muslims with terrorism ... even though most of today's terrorism on this planet is done 'in the service of Islam' ... and this is one almighty 'no-no' to PC adherents.
Thousands of worldwide terrorist atrocities later, and the PC brigade are STILL unrelenting in their demands to not 'demonise' Muslims. Many will even insist, in defiance of Islam's entire blood-soaked history, that Islam is 'a religion of peace'.
.... So. Do you seriously not think that, today, such a 'PC' climate aids terrorist cells ?? Cells who may kill .. HOW MANY people, given the chance ?
YOU tell ME ...
Wake up, Pete, and get a grip on unsanitised reality.