Yes, I'm aware that Illinois had a 'colorful' track-record during the Civil War...I dunno...
My family are dyed-in-the-wool Yankees thru-and-thru...
Illini for as long as we've been in this country...
Had I been alive back then, there's a good chance that I would have enlisted to wear the Union Blue myself...
However...
Acknowledging that Black Folk oftentimes see the Confederate Flag as a purely racist symbol...
To many White Folk with strong roots in the South (including Old Virginia), the Confederate Flag represents Rebellion Against Tyranny (perceived) and States Rights Trumping Federal and Courage Against Overwhelming Odds and stuff like that...
Personally, as a White guy, with no stake in this, I don't begrudge 'em their Old Flag, as a way to remember that part of their heritage...
https://www.youtube.com/watch?v=UVeSKwM--1M
I'm fully aware that this is not a Politically Correct stance...
Fortunately for me, that part doesn't bother me in the slightest...
This may interest you:
Illinois Copperheads and the American Civil War
After all, we touch upon two old Slave States... Kentucky and Missouri.
Then again, we're such a long State, top-to-bottom, that the northern part of the State, which holds most of the towns and population, was far more pro-Lincoln and pro-Union than some of our southermost and westernmost folk...
My own family roots her ein Illinois stretch back that far and we're all northeastern Illinois types where pro-Union sentiment was running at its strongest within our State...
And, in the final analysis, we did our bit...
List of Illinois Civil War units - Wikipedia, the free encyclopedia
...which is all that counts, when all else is said and done.