The IWM is not a museum that glorifies war. Its message is that war has been a phenomenon of the 20th century and the museum's purpose is to present its history in a cold blooded manner. Of all the war museums in Europe I've tracked down, visited and revisited, I don't think any would qualify as glorifying war. Maybe the Battle Gallery at the Chateau Versailles, even that can be disputed.
My last time there at IWM was in 2012. It is a museum with its permanent displays and special exhibition that focuses on war history and the effect on society. Yes, you do see machines...tanks, planes, machine guns, PAK guns, the jet fighter, artillery (incl. the 88mm FLAK gun all set up), They could do more here. If you read French and German, the respective displays would be even more enlightening. No tickets to the IWM, free admission., just walk right in. To do the museum justice, be prepared to spend min 4hrs going through all the floors.
Now, should you want a museum in London that focuses on more battle history, etc., I would suggest the Guards Museum near St James Park.