This is mostly confirmation bias since no one individual has the bandwidth or resources to look at every single story produced on every single topic on a single day. I tend to see people complain "this tragedy happened today and I don't see it being reported by the news!", implying that the media has something to hide or they value certain groups of people over others, but this is not a claim worth its salt.
There are many reason, both from the organization's standpoint and from the individual's standpoint, why this claim isn't true. It's a weak argument that only serves the purpose of distracting from topics at hand.