The US Bill of Rights is substantially expressed in negative terms, and addressed to the government. (”Congress shall make no law abridging . . .”, etc.). This is a relatively conservative approach to the question, by contrast with the Declaration of the Rights of Man and the Citizen, which dates from around the same time, and starts out with more positive language (“Human beings are born and remain free and equal in rights . . . The goal of any political association is the conservation of the natural and imprescriptible rights of man”). But the Declaration moves fairly quickly to provisions directed at what the government may or may not do (“The law has the right to forbid only actions harmful to society . . . No man can be accused, arrested nor detained but in the cases determined by the law . . .”)
I think the idea of defending persona rights by restricting the power or capacity of the government is a natural reaction to the fact that, government having so much power, the greatest threat to human rights comes from government actions. Hence earlier human rights instruments were focussed on limiting the government even if, like the Declaration, they started out with positive affirmation of human rights.
Modern human rights instruments tend to follow the French, not the US, approach, and start by asserting positive human rights, from which limitations on the power of government are derived, rather than by starting from limitations on governmental power. And this approach is more open to a legal culture in which rights can be asserted against the world, and not merely against the government, even if the practical focus is mostly on infringements by government agencies.
The Irish constitution dates from 1937, and so predates the UN Declaration on Human Rights. The constitution recognises that citizens have “personal rights” and requires the state not only to respect these itself but, by its laws, to “defend and vindicate” them. Thus the state is obliged not only not to attack your life, person, good name, etc, but also to provide a legal system which prevents, or at least provides a remedy for, such attacks by others. Which, of course, implies that others are obliged to respect your personal rights.
But, if they don’t, and if the law doesn’t provide you with any adequate remedy for that, then in the constitutional framework in most cases your complaint is not against them for infringing your personal rights but against the state for failing, by its laws, to defend and vindicate your personal rights.
But not in all cases — there have been cases e.g. in the area of labour law in which employers or trade unions have been sued for doing things which were said to infringe the constitutional personal right to earn a livelihood. But in most cases if someone else infringes your personal rights you will have a remedy under “ordinary” law - you sue him for assault, or for infringing the equal treatment legislation, or for defamation, or whatever - and the ordinary law is seen as the means by which you assert your constitutional rights against him.