This other website claims that title "X" is going to be released on this date. Why don't you have that date on your site yet?
In an effort to streamline information and protect their theatrical earnings, many studios have instituted Official Consumer Announce Dates (OCADs). No information about home entertainment release dates can be communicated to the public until a particular film reaches its OCAD. It's possible this other website in question is violating the OCAD or simply making up the information. Because we value our unique relationship with the film studios, we always adhere to official OCADs. This also means that we will always have the most accurate and most timely release date information on our website.