It has a lot to do with history. Back in the 1960s during the British occupation, they wanted to bring in the Chinese and the Indians together with the Malays and create a Malayan Union. The Malays gave them the bird and created UMNO, a government group solely focused on getting rid of the Brits and making Malaya MALAY ONLY.
Due to this, they started convincing the uninformed villagers (the Malays are the dominant uneducated race back then) to fight for Nationalism and stay true to their traditions, which includes going to mosques, maintaining polygamy and generally fight off whoever isn't the OG residents of the Malaya. (The Indians and Chinese were brought as slaves.)
This convinced the masses that in order to keep their country independent and free, they should stay true to their outdated culture in which women can't go for Mosque prayer sessions, men can have multiple wives, circumcision practices and a religious belief so true it took out two tower- nah, I'm reaching there. Compared to the Middle East, we're quite chill down here
Nevertheless, attending mosques now not only hold religious meaning, but also shows your support of your country, your independence and your forefathers' sacrifice.
Even under the looming presence of a virus who's primary prevention cause is to NOT be in giant crowds.