Moses performed miracles, parted the red sea, and freed his people from slavery…and there were still people in that group bitching and complaining every step of the way.
People literally witnessed God's intervention, in pillars of smoke and fire leading them through the wilderness, they witnessed raining manna, and springs of sweet water bursting forth from the ground to satiate their cries of hunger/thirst….and people were still out there like "muh but is God real tho?"
This is what always comes to my mind when I read concernfag posts.