The problem with people saying that this policy will cause them to stay elsewhere, is that a lot of them mean off-site, but still going to WDW. Meaning that Disney is still getting their money for park tickets, food, souvenirs, parking fees etc.
The other thing, and this is not directed at the quoted post above, is that these boards have deemed these to be "security checks". Disney has not used this term, and security is only one of many reasons that allows them to access your room according to the terms and conditions everyone agrees to when they book their room. Getting eyes on each room on a daily basis easily serves a number of purposes that are beneficial to Disney. The fact that most checks consist of someone simply looking into a room, or walking in, looking into the bathroom and leaving indicate that it is not primarily security focused. As others have pointed out, most Disney hotels don't have the line of sight to a highly populated area that the shooter in Las Vegas did from his room. And guests are checked before entering the parks. So the Las Vegas shooting may have simply provided a convenient time to implement this policy that accomplishes goals other than just security.