Fwiw, this could be a miscommunication - ENFPs tend to empathise by sharing similar stories, by associating them to their own experience, to show the other person that you're not alone. Another possibility is that they're not aware that you're actually needing to talk about this, but are just venting and that this is a 'mutual' griping session in which they can join in.
It's usually not meant to be competitive in any way and if you indicate that with 'listen, can I just talk to you about this incident for a sec?', they tend to be happy to oblige. If you point out the pattern to them, in a neutral, observational way, they might be incredibly embarrassed and defensive for a sec, but most look out for those situations in the future and adjust accordingly.
I honestly don't mean this to dismiss your gripe with our kind or to excuse it away, as it is legit - it is just meant as a tool to hopefully resolve these types of situations when they're in progress.
I'm not an ENFP, but I relate to this, and sometimes after I do it I wonder about it. When it comes to vulnerability and personal pain I don't like to say "I know how you feel" because that comes across to me as dismissive. By sharing something specific from my life I am letting them decide how much I 'know' how they feel or if it helps to connect. It is a way to meet at the same level.
I have some defensive against the idea of people assuming to understand personal experience if they don't. It isn't always about my own situation because I want to be consistent about it regardless which side of the coin I'm on. For example, I know people with extreme chronic physical pain, and while I have had some in the past, I know when someone is dealing with a lot more than I am. I don't want to relate an experience like saying, "oh yes, I've had headaches, but boy I never missed work" (Not true of me - had headaches, but did miss work, etc). I use that as an example because while you are sharing a personal experience, it doesn't match someone with debilitating pain, so it can be dismissive. It is better to say, "oh yes, I've had headaches, and even though mine weren't of the debilitating nature as others, I experienced enough pain to know it is nothing to mess around with," or something along those lines. I try to demonstrate enough personal experience or something to describe why I acknowledge or respect what they are describing.
Very bad pain is confusing and alienating even to rather nice people. People who have gone through difficult things learn that you can't talk about it or there is a bad social result. By sharing a personal experience, you are saying that it is comprehended and safe to describe the pain. People with horrible physical pain learn that often those without it cannot converse without being dismissive. People who have been abused or molested learn that many people who haven't will tend to have little judgments about it to subconsciously try to feel safer. It's true of all pain - that people who are innocent of it have a tendency to dismiss it even with the best intentions. This is not true of everyone, but it is a general tendency for people.
I think sometimes people do compete about personal pain as they share references, but I've also noticed that it tends to be people who's pain has not been validated in their life. There was a lady who made the headache reference I described above, and even though she likely didn't have the extreme chronic pain issue, I have noticed in her subtext that she has had personal pain that no one ever talks about or acknowledges. So, even when it feels like someone is competing, there can be a legitimate reason behind that. I don't think people are usually saying 'my pain is worse', but rather 'my pain was real'.
