There's probably a reason for the ban, but I sincerely doubt it's this one. Simply because other similarly reliable or worse sources are not banned. More like

There's probably a reason for the ban, but I sincerely doubt it's this one. Simply because other similarly reliable or worse sources are not banned. More like one individual started a RFC "Should we prohibit the use of The Daily Mail as a source?"[1] where 78 expressed themselves at correct time and place and the result was 54 for the ban and 26 against the ban. So Ban it is. Had 55 people voted against the daily mail would still offer the same reliability but it wouldn't be banned. Sort of a usual case of how wikipedia is run behind the scenes where a small minority of self-selected (white? male?) people with knowledge of the internal mechanisms of wikipedia decides in the name of all wikipedians to apply rules to the whole wikipedia and beyond (though those rules may not apply to themselves or their friends or people in the power structure)[2]. This case just got a little extra publicity because it concerned a known newspaper. [1]: https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources/Noticeboard/Archive_220#Daily_Mail_RfC https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources/Not... [2]: If a majority at Wikipedia decided that 2 + 2 = 5, then that's what Wikipedia will publish. Similarly, if a majority decides that "4" shall not be mentioned, then it will not be mentioned. On Wikipedia, fact, and truth, have no validity in themselves. This means that they are subject to political determination, i.e., the process of obtaining agreement. Those who believe that 2 + 2 = 4 will need to lobby for 4. Wikipedia has an exhaustive set of rules that purport to guide such discussions, but those rules are routinely ignored. https://en.wikipedia.org/wiki/Wikipedia:Why_is_Wikipedia_losing_contributors_-_Thinking_about_remedies#Facts_.26_Truth https://en.wikipedia.org/wiki/Wikipedia:Why_is_Wikipedia_los... -edit- interesting timeline here: - 2014: daily mail banned all its journalists from using Wikipedia as a sole source because of its unreliability. - 2015: wikipedia adds the daily mail to "should not be used when a more respected, mainstream source exists, or in place of such a source."