There is a potential negative consequence, when groups are together against a reasonable project, but can not agree on the alternative they actually prefer. That can be viewed in action in Germany with big infrastructure projects. In particular at the moment with the reconstruction of the Train Station in Stuttgart. Many groups are against the project, but have not compatible ideas on what to do instead. If contrarian groups get better at coordinating their protests you might end up in a situation where no productive project is possible any more.

In politics it leads to a part of the population to always vote for the other guy.