why folks think long covid isn’t real? Most disease have long lasting effects. Why not covid?
Without endorsing this one way or another: that's precisely the argument. There does exist a general "post viral syndrome". Since that is already known, why jump to the conclusion that a separate post-covid syndrome exists, as opposed to this just being another example of the same?
That might turn out to be a pivotal argument. But as it is, it proves too much: it denies the existence of a general post-viral syndrome. Since we do know that viruses, as a general phenomenon, can lead to effects like what are being reported, the default assumption ought to be that this is just one more such example. From there, researchers could attempt to show that this is (or is not) qualitatively different.
Skipping a known likely cause to search for something more specific seems like a potentially much more difficult path, and by pursuing it this way it also seems likely to miss out on the possibility of helping those suffering from post-viral syndrome that's not connected to covid.
Post-acute infection syndromes (PAIS) is an umbrella term. Many fall under this. Long flu(not new, but new research suggests the phenomenon based on long covid research), long rsv(not new, just more recognized when kids get it and develop asthma later in life), long covid, etc. Larger list here: https://www.nature.com/articles/s41591-022-01810-6/tables/1
Researchers are actively pursuing PAIS and the research being done for long covid is making breakthroughs in PAIS and PAIS populations like ME/CFS. It has become so prevalent that this year there have been multiple centers focusing on it. EX:
Nobody is skipping likely causes, if anything we are driving forward today on hypotheses that could help all PAIS (i.e. viral persistence, autoimmunity, chronic inflammation, reactivation of latent viruses).
Without endorsing this one way or another: that's precisely the argument. There does exist a general "post viral syndrome". Since that is already known, why jump to the conclusion that a separate post-covid syndrome exists, as opposed to this just being another example of the same?