Your definition of "Sober" - I'm confused

I apologize to anyone this may offend. That is NOT my intention. I am genuinely asking to learn because I am new to sobriety and AA.

I thought I knew what "Sober" meant but the more time I spend in the rooms the more I question what I previously thought of as sober.

To me - Sober is pretty black and white. You are not drinking or taking any drugs/mind altering chemicals at all. Seems like a lot of people do not agree with that. I think everyone agrees with the "no alcohol" part of sober, but it's the variety of drugs/chemicals that some people use to "stay sober" that comes into question.

When I see someone that is clearly under the influence of some medication to the point that they are clearly unfit to drive, slurred speech, etc...how do they feel so confident to share their success in sobriety and offer to be a sponsor, etc... I don't understand going up to collect a 6-month sobriety chip (or any sobriety chip) if the whole time you have been sober you have been taking some other drugs that obviously get you high as sh*t. It's weird to me and I don't get it. If you are strung out on Suboxone or Methodone or whatever else. How is that "sober"?

I think I should probably focus on my own mess and not judge other people on their journey. That feels like what the Big Book would tell me to do, and okay...I get that. I just wanted to see if I was alone in the confusion about what the word "Sober" really means.