But it's only your perception as to what those actions give away
The point is that you are choosing to interpret the actions in a way that
you personally feel is 'proof' of guilt. As others are trying to highlight, there are any number of alternative reasons, not least of which is a basic principle; that I don't want the police to access to my personal stuff. Whether these are plausible or likely (in your eyes) is irrelevant.
Guilty of a crime or not, I (personally) would not aid the police in searching my house. If they had a warrant, they could break in and there is nothing I can do about it. I would not resist, but I would not assist. Similarly, if they have a warrant for access to my computer, I would not resist, but would not assist. Passive and non-violent resistance; this has never and should never be illegal.
If they find anything in my home or on my computer that a court of law considers a criminal offence, I can be convicted of it. But my non-violent and passive resistance should not be in itself a crime. It is ALWAYS up to the state to prove guilt, and for you or anyone else to say "well a reasonable man would assume he has something to hide, therefore he should get a jail term for not co-operating" is absolutely abhorrent. Our legal system is NOT set up in that way, and we can all be thankful for that.
What you ASSUME should NEVER have a bearing on a conviction. Only what can be PROVEN beyond reasonable doubt.
You are arguing here from a position of pragmatism, I (as with others) are arguing from a position of idealism. In principle there is nothing wrong with either standpoint, but you are suggesting that in this instance, someone taking an idealistic standpoint should be convicted because they refuse to bow down to the pragmatic realities of the case (i.e. assist the police to read your personal data, or go to prison).