rd: To the extent that you are correct, I think you should give more credence to the idea that it is important to distinguish and differentiate from the apikorsim who try to destroy our religion.
The paranoia makes sense. And perhaps there is some legitimate innovation that would be allowed but needs to be suppressed because of it.
As it happens, the threat today is not from reform, but from Sperber himself. The only change he will have on judaism is a further retreat to the right in reaction to, and in paranoia of, him. And his movement, like every other movement that has split to the left, will eventually completely assimilate.
I’d say there is a better chance of my great-granddaughters wearing teffilin than of his.