It doesn’t make it unacceptable, either, if the country in question has done the same to others.
If Ireland was known to interfere with elections of other countries and then stated a country had done the same with their election - that would come under the category of ‘tough,’ or, at least,very hypocritical.
Needless to say, as you mentioned above, there is no evidence that Russia did hack the DNC emails, and/or what effects - whoever did so - had on the election result, if any.
What they are also focused on is making sure it doesn’t happen in the future. Apparently from what they said, the Russians did try to hack into some voting machines (but to their knowledge had not done so) and actually did hack into voter registration lists of various states and used these to target voters with disinformation.
I personally think all the Russian efforts would have impacted the vote, but not enough to have made a difference in outcome. I think it possible, maybe likely they caused some voters to switch from Hillary to Trump, more Trump supporters to turn out and vote for Trump, and/or less Hillary supporters to turn out and vote Hillary. I don’t think that is an unreasonable assessment considering the intense and varied active measures they conducted. There are lots of people in the middle who could go either way or may not be motivated much to go and vote – those are the people who may have been impacted.
What I don’t think is that the Russians would have swayed enough such voters to have made an ultimate difference in who was elected president (since our electoral college makes it difficult to do so), only in the numbers here and there in the states they mainly targeted. For instance, even if they had swayed 11,000 Michigan voters to either switch to Trump, come out and vote for Trump when they wouldn’t have, or stay home and not vote when they would have voted for Hillary, that only would have thrown Michigan to Trump when it would have gone to Hillary without Russian interference. But Trump still would have had enough electoral votes, even losing Michigan, to win the election.
Even if Russians had swayed 23,000 Wisconsinites, making Hillary lose Wisconsin – and without such interference Wisconsin would have gone to Hillary, Trump still would have won the electoral college.
In order for Trump to have won due to Russian interference, it would have to be that Russia interfered with some 45,000 Michigan votes, as well as with the tipping numbers in Wisconsin and Pennsylvania.
Do you see how far-fetched it is that the Russians would have actually thrown the election to Trump – it would mean that they had influenced over 78,000 voters to either change their vote to Trump, get out and vote for Trump, or stay home and not vote for Hillary in those 3 close states.
What the intelligence communities are concerned about now (and what we should be concerned about) is that their efforts and abilities will be increasing in the future, and that we need to do things to prevent the interference. Maybe next time, without our efforts and diligence to reduce or prevent such interference, the Russians (or some other foreign entity) just might be able to sway over 100,000 voters, and IFF it is a close election and those voters are in close states, that just might throw the election to someone the Americans would not have voted for otherwise.
Of course, if the Russians are able to get in somehow and actually change the votes, that would really be bad. We shouldn’t let that happen.