You could say it's smart business. Avoid paying E100 million in taxes in UK by routing sales through Ireland. So Microsoft has turned this large sum into tax revenue. There is a possibility that Microsoft will see court time for tax evasion. Many big corporations such as Google and Facebook are also facing scrutinization. Companies like Microsoft ruin it for everyone else, since suspicion will fall on other companies, as governments will wonder if these others companies are doing the same thing. The British government seems to be alright with it, as it has given approval. It may be that the media will have something to say. Whether there is a just claim of tax evasion remains to be proven; yet Microsoft could do without the bad publicity. All companies wish to avoid controversy.
Most of the money transferred in tax avoidance flows from poorer nations to rich ones. The biggest tax havens are the City of London, Manhattan Island, Holland, Switzerland, Luxembourg etc. London is becoming the money laundering capital of the world.
The EU is trying to insist on "country by country reporting" which will mean companies have to report where they earn their money so that country can collect the tax due. The UK are trying to exclude trusts which will see money move from companies to trusts and not solve anything.
By avoiding taxes in one country and not paying in the other Microsoft sets the bad example of how to be a responsible corporate entity. The only profiters are those who already have enough bank currency to not need extra free profits earned on the labors of the less fortunate. It's not going to go away and many other corporations are just as bad. It's time the small person, the small business has a voice and a share of the pie.
No, Microsoft should not get away with shirking on its tax bills. While it surely benefits Ireland and Microsoft monetarily to provide this work-around, the UK has been a valued customer and why Microsoft would even consider this seems a bit counter-intuitive. Does anyone believe that Microsoft is struggling financially to the point it wants to basically cheat Great Britain?