Divisive for whom?
The Bloc wants the federal government in Quebec to function officially in French only. And many English-speaking conservatives outside fo Quebec want an end to official bilingualism, at least as far as it requires many civil servants to know French for exclusively symbolic reasons, too.
So the Bloc would be happy with this, and so would many Conservatives.
The NDP just wants to see Canada stay together, so if this is so contentious an issue for many Quebecers, the NDP would likely grudgingly go for this.
The Liberal party would thus be about the only party left to support spending on symbolic bilingualism, which would likely thus hurt it in Quebec, and that too would likely pressure it to abandon such a policy.
And if they all abandon it, then the Greens likely would too.
In this respect, the Bloc could make this happen.