Perhaps that's because most of the electorate think recent governments have struck a good balance between civil liberties and security.The results of surveys on this issue are interesting.
A clear majority of people in the UK do typically back some of the stronger surveillance and security measures, when (as is almost always the case) they are presented as giving the police and security services greater powers to prevent serious crime and terrorism. I mean, who doesn't want to prevent serious crime and terrorism?
On the other hand, when presented with more complete information about the actual laws that have been passed, such as the much wider range of government departments who have been given such powers, or when questioned in a way that demonstrates they themselves are subject to the same intrusions, many more people express concern and a lot object strongly.
Surveys also show pretty consistently that the vast majority of people don't know even roughly what the actual situation is, and assume it is more the former than the latter. For example, many people didn't even know about the increased surveillance powers granted a few months ago. Popular support is based on trust in our government and public services, rather than knowing the facts.
lets face it if we believe that we have to argue the case before the public
Unfortunately, the political party with the most credible basis for arguing in favour of stronger civil liberties seems to have decided they want this election to be about exactly one issue, Brexit. Whether or not that strategy works out for them over the next couple of months, it makes it highly unlikely that other important issues like this will even make it into the public debate at all.