Earlier quoted context omitted.
Would you expect Linux users at your workplace to still be running Ubuntu 9.10 (Karmic Koala)? Or to be a bit more generous, Windows 7 SP1 is closer to Ubuntu 11.04 (Natty Narwhal). Neither of which have been supported for at least half a decade. Even Windows 8.1's equivalent Ubuntu 14.10 (Utopic Unicorn) fell out of support two years ago. Though arguably that's intentionally unfair because Ubuntu 14.04 (Trusty Tahr)…
While I agree with your main point, I find it odd that you'd even factor in the non-LTS/bleeding edge releases of Ubuntu vs Windows (10). The closest I can think of in the Windows world would be Windows Insider builds but those are a bit more akin to nightly releases (though that characterization is a bit unfair to Windows Insider). Yes, you qualify that with the "intentionally unfair" but I fail to see what it adds…
[For completion's sake: 8.04 (Hardy Heron) is the roughly closest Ubuntu LTS to Windows 7, and hasn't been supported since 2013. 10.04 (Lucid Lynx) was the closest LTS to Windows 7 SP 1, and also hasn't been supported since 2013 (on Desktop).]
I used the more closely aligned dates because Windows and Ubuntu have been aligned to similar-ish 6 month cycles for a while now and especially in Windows 10. It's interesting that the LTS equivalents are in opposite parts of the cycle with Ubuntu LTS in the Spring and Windows LTS in the Fall. But even accounting for LTS versus LTS, the fact of the matter is that Windows extended security support still dwarfs the comparable Ubuntu timeframes and few are complaining that Ubuntu's support windows are too short. Of Desktop LTS support, Microsoft's seems almost by far the longest of any Desktop OS/distribution and no one is expecting Desktop support for even a Linux LTS distribution support like they expect from Windows.