I admittedly am not very good at debating, so I will really challenge myself now. ... look at recent events ... I feel like intolerance and bigotry in religions is obvious and obviously harmful to any society.

Ok, good, Now, to make a good argument you should do the following. First, find a few specific recent events and then link them to the religions themselves. Given that you are targeting all religions, you should have at minimum four different religions represented. I'd Recommend Islam, Bhuddism, Hinduism, and Christianity. Taoism would probably be my choice for a fifth Second, show that this is a pattern of behavior common to the religions. Theoretical reasoning will be important here. You have to not just link them being religious to their acts, but you also have to rule out other non-religious motivations. Third, you have to explain why without religion, humanity will be better off then with religion. Something you will need to consider here is how religion is different from other similar things that are forces for good.

Your big challenge is tying all religions together rather then a subset. Saying that 'Religion poisons everything' is a very different statement from saying that 'Christianity poisons everything'. You have to consider the full spectrum of religious beliefs and how all religions (rather then a subset) poison things.

If you did that, you would probably have a good argument. Not great or ground breaking, but good.

TLDR; 1. Find examples of intolerance and bigotry in religions. 2. Explain why this applies to all religions, not just the ones sampled. 3. Explain why without religion things would be better.