We don't know who filled your head with such silly notions but no, that is not remotely true. In fact, in recent years, several Strip casinos have warmly embraced the LGBT community, with the Tropicana the latest hotel to launch a gay-friendly sub-site, joining the ranks of Paris, Luxor, Caesars Palace, Mandalay Bay, MGM Grand, and Wynn as being notably gay-friendly. If you're venturing off-Strip and/or prefer a more boutique hotel experience, you'll find Artisan and Rumor, owned by the same group, to be very accommodating, also.
Your query (no pun intended!) prompted us to do one of our famous call-arounds and we can confirm that of the 60 wedding chapels we're aware of currently operating in the Vegas Valley, 45 offer a commitment ceremony, of whom all but six are happy to accommodate same-sex couples (only nine responded with an outright "no" to any kind of commitment ceremony.)
The six that offer commitment ceremonies, but not for same-sex couples, are: A Special Memory; Allure; Chapel of the Bells; Hollywood Chapel; Vegas Wedding Chapel; and Wee Kirk O' the Heather. The nine that do not offer commitment ceremonies at all are all non-hotel chapels, including: A Las Vegas Wedding Chapel; A Little White Wedding Chapel; Always and Forever; Elvis Chapel; Graceland Wedding Chapel; Heavenly Bliss; Lily of the Valley; Little Chapel of the Flowers; and Little Church of the West.