Nothing silly about it. The law does allow for different individuals to be paid different amounts. The issues raised by the Equalities Act pertains to arbitrary discrimination for pay for the same work under otherwise the same terms of contract. If individuals want to bargain for their own pay conditions, let them. The employer can't be forced to pay them the same simply because a group of other employees have, in their individual group, negotiated a pay-rise.
His loss. Leave him to it. He's got enough on his plate without your moral indignation to add to it.
On the other hand there are many "decent employees" who are happy to fight their own battles and those of others without the need to participate in a unionised structure who are acting perfectly properly and perfectly sensibly. The mere fact of a union structure does not give it moral superiority over anyone. That seems to be something you can't accept.
Oh and democracy is a travesty of a system. Granted, the least worst save a free market of ideas, but a total travesty nonetheless.