What a completely ridiculous statement from the 'DWP source'. As has already been stated, this demonstrates the complete ignorance as to the mix of properties actually available to those people in housing need, and the mismatch between single people needing housing and 1-bedroomed properties available. Furthermore, however, this statement completely disregards the perfectly reasonable motivation, which had previously been encouraged, towards providing sustainable housing.
Providing a 2-bedroomed property to a young couple (a) because they're in desperate housing need, (b) because there were no 1-bedroomed properties available, and (c) because at some point within the next couple of years they may require a further bedroom anyway and could wait many years on the transfer list for a property (being in lesser need perhaps, because they have secure, self-contained, albeit overcrowded accommodation), provides a much more effective and longer lasting solution to their housing need.
As with many aspects of these welfare benefit changes, the ideas of sustainability and sustainable communities are beyond the comprehension of this government, as are the prospects of future instability that this community of nomads they will be creating will inevitably lead to.