This questioner from Europe asks; is not cooperating with Salafī Islamic centres and mosques populated with people of Sunnah considered abandonment of the Jamāʿah, and what is obligatory upon us to do?

Shaykh Ṣāliḥ ibn Fawzān al-Fawzān

Oh yes. Abandoning cooperation is due to laziness and not wanting good. Cooperate upon righteousness and piety and do not cooperate upon sin and transgression. [Q 5:2]. Cooperate. Be ardent upon cooperation as long as you have the ability to do so. Cooperate with the people of righteousness and piety and [those who] call to Allah.