Mitt Romney closed his Facebook wall on June 5th this year and Paul Ryan followed suit on August 17th. Neither Obama nor Biden have had open walls during the campaign. Do we approve? No. It's not very 'socially devoted', but going through some of the pretty negative user posts, it's not surprising. Interestingly, 'pro Ron Paul' mentions made up more than 10% of Romney user-generated posts from the first of the year until the closure of his wall.
Disclaimer: Here at Socialbakers, we make a lot of noise about the Engagement Rate as the master metric for rating your social success and generally this holds true - even if some of the feedback is negative: "the only bad publicity is no publicity". Negative comments are an opportunity for brands to catch and address issues early and turn any rising tide against their product or service. But this is not necessarily true for politicians running election campaigns. Their 'non-fan' contingent, their unwilling constituency, will (more) often (than not) post negative comments, tirades and off-topic distracting diatribe that can (slightly) dilute the value of their "Engagement Rate".