I would define hate speech as words that attack, invalidate or otherwise demean anyone from an individual to a broad group of people. It is unimportant in what way this speech is communicated.
As in all matters concerning free expression, especially when taking the Internet into account, it is incredibly difficult to find a balance between unsatisfactory restrictions and oppressive suffocation of free speech. The most important idea to uphold, in my opinion, is treat every forum of communication individually. There are certain communities, especially online, that would lose their integrity if they were to be policed for hate speech violations, and at the same time there are places where a firm level of control makes perfect sense. A big part of this is the wide variety of intention behind the words we call "hate speech". An adolescent boy flagrantly spouting homophobic slurs while playing Call of Duty should not be treated the same as a shopowner rudely dismissing customers because of their race. Finally, an observer needs to understand that depending on their situation, they might need to prepare themselves to hear hate speech, because it isn't always under control.
I would be incredibly wary to even consider attempting any sort of international consensus regarding hate speech. Hate between ethnicities is one of the more primary forms of it, and thus, the issue would have an insane degree of sensitivity. I can firmly state that the international stage is not the proper battleground against hate speech, because even if it was decided that certain nations were not up to the standards, outside attempts to intervene would be looked at very negatively by the majority of people, I imagine.
Depending on the website, having a filter on user comments against flagrant hate speech (being careful to not overreact and ban users who aren't hating) isn't a bad idea. However, I think a distinction needs to be made between site content and user input, i.e. comments. Sites openly promoting hate speech should be put under some sort of scrutiny, though I hesitate to take too far of a step there, but they should never be held responsible for tasteless or hateful comments. It's well known that Internet anonymity leads to completely vicious behavior among many individuals, so while this may be ugly, it remains an unavoidable reality, an unfortunate fact of human nature. Comment sections always must be taken with a grain of salt.
As stated above, I am not sure what sort of action should be taken against such creators, but I firmly believe that they are not to be held responsible for the actions of other individuals who have simply viewed their material, unless there's some sort of direct instruction or incensing of the individual to do what they did. Most recently, the ugly attacks on violent video games show how dangerous it is to assume causation from correlation.
The only plausible way to achieve restrictions for children against hate speech is to bar access for them to sites that offer the sort of freedom that might lead to hate speech getting through. Unfortunately, it's hard to do anything but leave this up to parental discretion without entering oppressive territory, as there are countless sites that are fantastic sources of both information and entertainment but also might contain inappropriate material if a wrong turn is taken.
The short answer is yes. The long answer is that since different communities/sites require different standards, it is likely to find looser standards online, especially since it's very hard to ever have the anonymity found on the Internet in the offline world.
The standards for age-restricted content should absolutely not be even compared with those of hate speech. It's not as if we reach a certain age as humans where suddenly, discrimination is okay! I won't go into my thoughts on the insanity of what is and isn't restricted to youth in America, but regardless, there is a great difference between the two. The only reason I believe that the restrictions placed on youth over what they can view should lift as they move out of childhood is that hate speech is merely a necessary evil in a great deal of online communities where the benefits outweigh the negatives. Individuals need to develop the ability to see it and immediately dismiss it, rather than getting wrapped into it or worse (hate speech is a prominent form of trolling, and online, it can be very difficult to determine the poster's true intention). Hate speech is very bad, but the online venue is unfortunately one where eliminating it might be an impossible task do complete without sacrificing too much on the way