You're probably correct about Major, Bush and Mitterand; after all they (especially Major and Mitterand) shamefully colluded in Milosevic's destruction of Croatia and Bosnia-Herzegovina, and there is no reason that they would have behaved any differently over Kosovo.
Yes the bombing was justified. NATO's bombing of Serbia can only been seen in the context of the Milosevic regime's long histroy of aggression and destabalisation in the region.
I've always found the claims that NATO only bombed FRY because it was "communist" to be pretty baffling, quite honestly. The Milosevic regime's credentials as a ‘left-wing’ regime were pretty poor: Milosevic’s ruling party was called the ‘Socialist Party of Serbia’ and had formerly been the League of Communists of Serbia, but SPS leaders Milosevic and Borisav Jovic emphasised from the start their commitment to free-market reforms. Under their tenure the gap between rich and poor massively increased, social services were greatly reduced, free healthcare effectively ended, public transport collapsed, and a large new class of black marketeers and organised criminals created (those who point to Kosovo's organised crime problems, almost all of them with an agenda agaisnt Kosovo's independence, rarely mention that in the 1990s Serbia was a virtual mafia state).
Not only that, but until 1999, the West's policy was, if anything, quite favourable towards Milosevic. It supported the JNA's intervention in Slovenia, and (initially) its invasion of Croatia, it attempted to get Croatia to consent to changes to its borders, it imposed and enforced the arms embargo in Bosnia, and from the very beginning it legitimised the SDS's and (Boban wing) HDZ's platforms of ethnically partitioning Bosnia-Herzegovina. This policy of appeasement culminated in October 1995, when Karadzic, on the verge of total defeat, was ignominiously rescued by Western deplomacy, and the Bosnian government was imposed a territorial settlement which was quite favourable to the Serbs (they got 49% of Bosnia, despite having less than 1/3 of the population, with more autonomy that was ever offered to the Kosovar Albanians, even though Kosovo was a legitimate entity of Yugoslavia, whereas Republika Srpska was an entity created purely out of military aggression, ethnic cleansing and genocide).
Milosevic showed himself ready, time and time again, to collaborate with the US and the West, he sold much of his country's assets to British companies and supported the liberation of Kuwait. The problem was that his collaboration came at too high a price - acquiesence in Great Serbian genocide and expansion in front of the TV cameras, and in destabilisation of the entire region. It is in this context which the bombing of 1999 must be viewed.