Pain is deeply traumatic for people. It alters, usually in a lasting way, how we see and process the world around us.
As a result, there are many different defense mechanisms we employ to shield ourselves from the effects of that pain. For some, they enjoy escapism. Some people vent and rant and ramble. Others sublimate it into something like anger or detachment. And for others still, they have an optimistic approach where this hardship is a lesson or a test or something to help us learn.
Who's to say that there's a right way to cope with something traumatic? We don't really choose the things that ultimately heal us. But it is important that we move on in order to make sure the rest of our life isn't permanently bound to these past traumas.
I guess the point of saying something like that is prod people into moving on from it in a constructive way. When you can rationalize some benefit to something, it makes it easier to accept the pain. It's like breaking up with someone you love or quitting an addiction. You prioritize the long-term over the short-term.
What it makes it really inappropriate to say is that emotions are always short-term, and we need time to get over them before we can think about the next stage
