You are right, tolerance does have to go both ways, but why the demands for everyone else to be tolerant when the priest was being completely intolerant? The 'Get those posters out of this church!' reaction mentioned is anything but tolerant.
Tolerance would have been if he had allowed the posters, you know, as in 'tolerated their presence'. Doesn't mean he had to agree with, or even enjoy their presence, but by asking for their removal he showed just how intolerant he is of anyone not of his narrow views of the world.
The right thing to do would for him to have taken a deep breath, realise it was only for a day or two, and left them to stick their posters up. He might have come out looking good, and even helped to convince those of us outside the church that they aren't all preaching do-gooders with a chip on their shoulder.