is diversity a strength?

I think diversity can be a strength. The availability of different perspectives, rooted in different ways of life, can provide us with a way to see the world from alternative vantage points, and that can enrich our own perspective. But what if you live in a pluralistic country so fanatically focused on pluralism that it forgets to stress the notion of common values that bring us together? This is, I think, the question that conservatives find disturbing: when wave after wave of unassimilated immigrants arrive and dilute the local culture, eroding social cohesion and ignoring local customs and values, can a nation survive? That's essentially the point that Paul Joseph Watson is making here:

The West is committing suicide by immigration. Turned down to a reasonable trickle, legal immigration can be a good thing (as long as we're taking in immigrants who will be a net positive to the country). But as things stand now, with a torrent of immigrants—legal and illegal—entering the West, we're past the saturation point. What's the answer to this? Maybe start with strict numerical limits first. Do that, then deal with the problems at home, perhaps by starting a massive education program to inculcate Western values. Of course, it may already be too late: we've already given away the store, and the left, unwilling to see that there's a problem, is like people on the Titanic who compliment the musicians while the huge cruise liner slips beneath the waves.