Every human alive is too complex to be captured entirely by a singular ideology. It makes thoroughly more sense to ask for their opinion on particular issues, and when you do you will find that on each issue their opinion can be placed on the spectrum between right and left wing, conservative or progressive, freedom or tyrannical.
Ergo, the centre doesn't exist. You do have to be one or the other.
As for the nebulous concept of 'middle ground', consensus only works when both sides are willing to play ball or are interested in the best possible outcome.
And yet msm and social would have us believe that no one is centred.
I took the spectrum test and found myself pretty much bang on in the middle.
But nah, have to pick a side.