The UK was in genuine danger of being starved into submission by German U-boat attacks in WW2 that were sinking merchant shipping. It only reversed that because it was able to break the German codes and avoid or sink the U-boats. It was devastating for Germany to have its codes compromised. It would have been devastating for Britain not to have broken the codes. The current flavor of "information wants to be free" "patriot" would reveal the information that Germany's codes were compromised, and its messages were being read. The result would have been the starvation and surrender of the British isles, the transfer of the British government to another part of the Empire, some form of Nazi triumph, a much longer war, several genocides completed, and many more people dead.
Probably well over 100,000 documents of highly classified information on UK and US intelligence operations and methods were stolen and given to third parties. This is the same general type of information that was dealt with regarding the German Enigma codes, in some cases literally, since it is exposing encryption methods that the US and possibly UK can break - information that they shared in WW2.
I don't mean to insult you, but I think you show both incredibly limited insight and humility to say that what they are doing falls only into the category of "UK CLAIMS" it is damaging. How can it not be damaging for a government to have revealed what encryption systems it can break? How is it not be damaging for it to have its intelligence methods and operations exposed?
You should be clear that genuine damage to the security of a nation is a separate question of whether or not you personally approve of that damage. You should also consider the fact that there are likely to be consequences to it. It may take time, perhaps a couple of years, maybe more, maybe less, but there are likely to be consequences. You may find that you have been hasty in your approval.
On an off topic, I read today that a prominent nuclear expert thinks Iran could have enough enriched uranium for a nuclear weapon in about one month if they surged, and Iran has recently announced a significant increase in the number of nuclear related sites. I also recall that about 10 years ago, maybe more, they had formed a brigade of suicide bombers to attack US facilities and military personnel around the world.