There’s no paradox. He’s missing two big concepts:
just because they’re technologically superior doesn’t mean their technology to hide is 100% effective. There are certain basic difficulties with things invisibility. And we did learn when we came up with stealth aircraft that they had a problem with old style radar systems, they just send out the radar with too much oomph. Sometimes old tech can win.
And 2nd maybe they don’t always want to hide. We don’t have our subs always run silent. We don’t exclusively send our stealth aircraft into enemy territory.
“just because they’re technologically superior doesn’t mean their technology to hide is 100% effective”
This is the key thing the author is mistaking. Advance maneuvering technology does not automatically mean some sort of cloaking device. There is no reason to thing such techs would go hand and hand.