There is no technical reason for dropping IE6...perhaps. But, well, there's a business reason for dropping IE6: Time doesn't grow on trees, either, and it's plain impossible to support every <2% browser out there (Netscape Navigator 4.78, anyone?). Every browser that is supported also needs to be tested etc.
Dropping IE6+7 support has freed significant time on each project where I've experienced it (which could be better spent elsewhere, e.g. in IE8 support ;)).
An ironic message considering it was written on a platform which doesn't support IE6 or IE7.
Not supporting IE10 touch is lazy - draw.io is unusable on a Windows 8 tablet.
Telling other people they are lazy is just incompetent ;-/