It's pretty cheap to spend 50 PP on the "secularism" decision after you ratify the six(or was it seven? I forget, lmao) arrows. It has a 50% chance of spreading the kemalist modifier to an unaffiliated state, or 50% chance removing the penalty from a traditional state and transforming it into a 5% construction speed improvement. However, even with the latter option, it will remain traditionalist forever. There will be no real way of removing that and replacing it with a kemalist modifier, so like AnssiA said, you want to basically take the decision as frequently as you can, at least until there are no more unaffiliated states.
You don't really want to ignore it either ,as the traditionalists will keep expanding until there are no unaffiliated states.
It might be different if you are taking the path in the focus tree to get Fevzi Cakmak. He has unique focuses to actively cooperate with traditionalists and turn those negative modifiers into pretty positive ones. I'm waiting for a patch for Turkey to get its missing research slot available before really playing around with it more.