Correction: You mean custom, instead of costume. Yes, maybe I generalised. I was speaking about those groups in Somalia, especially the youth group. Yes, I know that J is waajib, but they are hardly following the correct, wise, guidelines.
In their aqeedah is they have the following:
1) No talks with the opposing side
2) They have a right to fight. Meaning, they will cause a war just to exercise that right.
3) The end justifies the means. If civilians and innocents die, they will be raised with their deeds.
4) No diplomatic relations with any kuffar people. Which raises the question, do they make their own weapons?
So, yes they are against modernisation. No state can be created that will be modern by such people.