Really and who again told you this? Secular science.
Basic logic and reason. Glaciers only move so fast. So if we have 10 glacial advances and retreats, we might expect such a process to unfold over thousands of years.
And if below those ice ages we have 5 oceanic trans and regressive sequences, in conjunction with compressional faulting, we have thousands and millions of years more. Physics only allows rocks to move so fast before they crumble or melt.
And if between those oceanic transgressions, we have animal tracks, feeding traces, nests and complex burrow networks, then we logically know that many years passed between transgressions. Life lived, walked, ate, bred etc.
And if we see double overturned angular unconformities, marked by slicken sides, fault gouge, more trace fossil burrows and cataclastic deformation, all below the oceanic trans and regressive sequences, then we know that millions of years further passed, because rock only hardens and is deposited only so fast. And rock only moves so fast according to basic physics. A
if animals are burrowing into the layers before they harden, that takes time. It takes time for the layers to then harden. Time for the layers to become orogenically tilted, time for those hard layers to erode to grade, time for new layers to be deposited, time for life to live and walk in those new soft layers, time for those new layers to harden, time for those new layers to be tilted, time for further new layers to be deposited on top, and so forth.
Young earthers tend to believe in a pre-flood world of just 2-3000 years. But the above events just cannot unfold in such a brief amount of time. Not by any logic or reason.
The green River formation had over 5+ million laminations. The formation is also shaped like a prehistoric freshwater lake. It's geochemistry indicates a fresh water origin, as does it's Flora and fauna.
5 million varves cannot form in 2,000 years by anyone's logic or reason. Some Creationists alleged that the varves are from waves of a global flood, but waves are not oval/lake shaped, nor do waves make deposits that look like a prehistoric lake.
It isn't modern science that teaches us that young earth creation doesn't make sense. It's just common knowledge that young earth views don't make any sense.