So with all this nonsense LGBT stuff, the symbol of the rainbow is often presented with it.

There is a reason for that; it isn't just different colours of the rainbow associated with different 'genders', there is a hidden (new age) meaning of it:

The rainbow refers to 'the rainbow bridge'. The rainbow bridge stands for the concept of a stargate or spiritual illumination. So it stands for a paradime shift in awareness or conciousness. In other words, a bridge in worlds of thinking; the way we perceive reality.

Now You know why some keep pushing this rainbow symbolic. 😉