Civilian infrastructure is infrastructure explicitly created primarily for civilians.
As you don’t seem to understand the difference between the Brooklyn bridge and military pontoon bridges, it is no wonder that your countrymen under Putin don’t understand it either
If the Brooklyn Bridge is utilized by the military, it ceases to be a ‘civilian infrastructure’. If a dam, which provides power to electric run trains and those trains are utilized by the military, it ceases to be a ‘civilian infrastructure’, as does the dam which is providing any type power utilized by the military. I could go on and on, but again, I got firewood to collect for a donation fund for Germans.
What’s ironic, of course, is that Putinists are just fine with Russia shoving every last Ukrainian into ovens. They just can’t admit it here lest the uninformed catch on to their bloodlust and nutbaggery.