code needs a small tweak

see this url https://ww.wp.xz.cn/support/topic/plugihow-to-remove-the-default-footer-proudly-powered-by-wordpress-theme-etc?replies=15#post-3544498

specifically:

@utnalove You’ll want to remove the ‘ around the false value, otherwise Infinite Scroll will look for <div id=”false”></div> in your theme, instead of actually disabling the footer.

add_theme_support( ‘infinite-scroll’, array(
‘container’ => ‘middle_single’,
‘footer’ => false ) );

https://ww.wp.xz.cn/plugins/genesis-jetpack-infinite-scroll/