I think the left wing have been fairly effective across the board on social media at shutting down opposition. If people disagree with the left wing it tends to be policy etc which is debated. If people disagree with the right wing it tends to get very personal very quickly (scum, bastard, greedy, racist etc, etc, etc). And on here at least it can follow you away from the original thread and impact on your enjoyment of other parts of the site because people remain hostile on other threads. And I'm not even particularly right wing, I actually voted Lib Dem. So it's unsurprising that people are reluctant to be as vocal about their support on social media. I think that very much skewed the view pre-general election, because I know a lot of people were convinced Labour were going to win purely because SM was wall to wall support for them.
I think RL can also be similar. When you're at work, particularly in the public sector, or jobs which have links with the public sector, to admit you vote Tory would be career suicide. Which is completely and utterly wrong, your political affiliations should be irrelevant to your career (unless you're a BNP member applying for a job as an equalities officer or similar.)
Incidentally, I'm going to lose money from the tax credits cuts and I'm actually in favour of them. I do not think that the government should be subsidising companies which make massive profits to pay very low wages. I also think that life got worse under Labour for all but those at the very, very bottom and those who were quite a bit above the middle anyway. Yes they might have chucked tax credits at people like me, but the huge increases in housing costs combined with stagnating and falling wages has meant that standards of living have dropped since 1996 for the working poor. I also feel that society changed during the Labour years, the way people behaved, how they treated one another, how they took responsibility for themselves, their families and their actions; it never, ever felt like positive change. And some of that was reversed under the coalition IMO.
My viewpoint is also highly coloured by the fact I worked in the public sector during the Brown years; during that time I saw absolutely obscene jawdropping amounts of money wasted on a daily basis which provided zero benefits to either the patients or the NHS itself. I have never really trusted Labour after that. And that is also something I profited from, I was paid £32k a year to do a job that didn't really exist and basically sat in an office all day playing computer games because no matter how much I pestered there was no work for me to do.