These include the emergence of primitive life from non-living matter (known as abiogenesis).
This is their biggest reason and their biggest mistake. I doubt this happened on earth. Life likely started on thousands of planets over billions of years before the earth was formed. Some of these life-sustaining planets experienced explosive catastrophic events (supernovas, collisions with other planets, etc...). Comets would travel through clouds of life and seed other planets.
The more planets seeded and exploded the more life would be spread through the universe by these wandering comets. Earth is young compared to the universe, so the seeding of life could have been occurring for billions of years, spanning millions of planets. Look at the moon and see the impacts, maybe even a few life seeding comets struck it too, it just that it wasn’t suitable to sustain life.
If abiogenesis occurs, scientists should be able to easily recreate it, and I am happy to set aside a minute to watch them do it.