The difference is that the Vulcans were ignoring Earth. If they had known that Humans were about to break the light barrier, then they would have kept a much closer eye on us.
It's not a good idea for the first time you meet a new species to be when you bump into them out in space. You know nothing about them, so you don't know whether approaching them with shields down will be viewed as a sign of friendship or as a sign of weakness. Doing your research on them before the encounter in space is a better idea - you know how to prepare for them.
Err, that's what diplomacy is for. This is why ambassadors and diplomats tend to be amongst the most educated and culturally sensitive that a nation has to offer.
It's not as if spying itself is not an insult or a dishonor or a a sign of contempt. Just catching a spy could be a disastrous act of war. Heck, spying in itself is a considered a serious and heinous crime against a nation. For that matter, whenever a Trek crew (across ALL the shows!) discovers that they were spied/tinkered upon by some higher alien power, the episode almost always goes into how violated and threatened the crew feels, even if the aliens are simply looking for some cultural insight.
Do you guys even know what a review is?
I think we as a society are coming to a point where we confuse media non-bias with opinion pieces.
I'm sure someone's going to complain about a columnist being unprofessional for giving his or her viewpoints instead of just reporting the news. Same deal with newspaper editorials.