How exactly do you envision this going wrong?

The rack itself won't hold electrostatic charge, and if the devices themselves want to be grounded they can be grounded through their power supply

And wood isn't that easy to get to burn unless you turn it into small particles first

I once worked in a hardware lab that used wire shelving for holding arrays of running machines, and a bad ground running through one chassis caused anyone who touched the shelf to get shocked by something very close to line voltage.

I’m more worried about heat dissipation though.

That shelf is more glue and fire retardant than it is wood. Its also really bad as a book shelf so it might still be superior in this role than the intended one.