Because "the system" has to follow IRS instructions.

"The IRS urges anyone who needs an extension to request it electronically by April 15, 2025. Though disaster-area taxpayers also qualify to request a tax filing extension between April 15 and May 1, 2025, these requests cannot be filed electronically. They can be filed only on paper using Form 4868, Application for Automatic Extension of Time to File U.S. Individual Income Tax Return."

https://www.irs.gov/newsroom/irs-reminder-disaster-victims-in-twelve-states-have-automatic-extension...