Unconstitutional is an argument that tends to have more weight. Immoral is a weak position to take when my opinion on morality and yours probably aren't the same - and for most people surveillance is full of grey areas.
Aren't they already? Ethics are subjective. There is always a minority that disagrees with the ethical basis for any given law. But there is an ethical basis that prompted getting the law passed.
You missed a pretty vital part of this - which is that laws are derived (at least theoretically in a democracy) from the majority view on ethics and morality.
We are a democracy once every 4 years ... and that extends only as far as the legislative branch. Our government(s) are composed of more than just elected representatives. We have civil servants that propose and draft the law, judges that interpret it, and police officers who enforce it. Do any of these groups give more than a passing damn about elections or the will of the majority? Or are they more easily subverted by the glare of the latest media frenzy, selfish consideration of their own career advancement, or innate primal urges towards jingoism, nepotism and authoritarianism?
Unconstitutional is an argument that tends to have more weight. Immoral is a weak position to take when my opinion on morality and yours probably aren't the same - and for most people surveillance is full of grey areas.