What does excluding one particular state prove?

Nothing.

Why not exclude Texas?

Pointless.

The Electoral College simply diminishes the value of the votes of those in the more populous states because many of the rural states, which tend to vote Republican, have Electoral College votes in greater numbers per capita than larger states.

That's fundamentally anti-democratic.

Is it democratic to have  a voter in a small-population state have his vote carry more weight than a voter in a populous state?