I read this more of a proverbial type statement that isn’t meant to be universally applicable. It would be basically arguing, from the context it was said in, that rich people may be more wedded to their money than the demands of the kingdom / faith. This was exemplified in this context by Jesus’s demands on this particular individual
Are you referring to the gate here? As far as I know many scholars argue that there is no evidence that any such gate named this existed