If they are discussing something important, then that's fine by me, but they are discussing irrelavant topics. For example, they talked about song lyrics, some random facts, keep asking the same question over and over again even after we told and reminds them so many times. IT IS SO ANNOYING I CANNOT STAND IT! Then this guy was like "I cannot stand people who leave the group. I have 0 respect for them." and ironically he was the one spamming the group. People in the group told those spammers to stop spamming but apparently they don't understand the meaning of 'no spamming'. I have no idea what's their problem. So I am here to share or maybe help you all to deal with this kind of things(based on personal experience).
Firstly, if the group is important to you maybe it's a Whatsapp group for some project. Then you got to deal with it.
Secondy, if the group is like semi-important to you. Maybe like an event is coming and you're inside the group. Then you mute the group, that was what I did initially. I mute the group for 1 week. So muting in Whatsapp means that you will not get notifications from the group but you can still see the messages. But my friend said it did not stop the notifications. Well, this is getting confusing. After the choice you selected ended, whether it's 8hours, 1week or whatever, you'll resume receiving notifications from the 'spamming' group. For me, after 1 week of muting the group. I selected 1 year instead, because I cannot stand them.
Thirdly, be sacarstic with everything you said. Apparently, I am being very sacarstic in the Whatsapp group because for the nth time, I really cannot stand them. Everytime they said something, I became sarcastic. (I did that less than 24hours ago.) I don't think that will stop the spamming though. But I find it a joy to be sacarstic to them. Well, it works for me...
Lastly (most extreme), if the group is like totally useless to you. Like a group chat for people to chat and stuff in addition that they are talking things that are 'testing your intelligence' (quote from my friend), and you kept wanting to leave the group, by all means, you may leave the group. That's what my friend did. She left the group with drama. Apparently she left this message in the group and left afterwards. Which I really admire her courage to do that.
What happened next is that the group became quiet and peaceful. End of my tips and tricks. Thank you everybody.