A statement like that should be followed with "I have spoken ".
As long as I have decent cables I can't tell any cable differences for my ears in my system. My current speakers are good, but I previously had some speakers very sensitive to every system adjustment. For me it drove me crazy trying to get them dialed in to sound their best.
On average I'm less able to perceive subtle system differences than other critical listeners. My girlfriend is not an audiophile, but a cello player. She has one particular test track that she knows very well and how the instruments should sound. I sometimes cringe when we use it to test gear because if she hears something off, she's usually right.
I don't think different cables will do much for me right now, but maybe they will at another point. I know just because I haven't experienced something yet with my limited sample size doesn't mean it doesn't exist.
When I do want to try to understand some of the electrical theory, I have found some technical articles by Nelson Pass to be helpful such as this one:
https://www.passlabs.com/technical_article/speaker-cables-science-or-snake-oil/