I noticed the same thing on reddit. Pretty much everyone acknowledges that the timeline we're using is the New 52 timeline which began in 2011, as there is no event you can point to after flashpoint in which it "reset." It would run counter to everything we've seen in death metal. There have just been adjustments and reshifting to the 2011 timeline, with everything rolling into it and both the old and new being made canon by death metal.
Here is what I believe may explain the difference between those who are accepting of what took place since 2011, which is most, as opposed to the pathological-seeming "revisionist" behavior we've seen from
one or two people here:
Newer fans, who are usually on the younger side, very much do not care for linear continuities or timelines, nor do they believe such things need to exist. What they care about is if the story is good. “Canon” is not really a thing anymore as others mentioned, and if it is, DC wants it to be additive, not restrictive. Nothing deleted, nothing discarded. This is a very much a generational difference. The younger crowd’s perspective is sort of “post-modernist” in the sense that truth is malleable and dependent upon perception, time, and context.
They just want good reads. DC has caught onto this and is catering to it with Infinite Frontier at least for now.
Its very much the older fans who care obsessively, almost pathologically, about maintaining a single orderly continuity. They
really do not like idea of a comic universe composed of independent, self-contained stories that don’t reference one another or do so in what they believe is an inconsistent manner.
Actually, they hate that. Some might even be brave enough to own up to this. For them it makes it all feel like it “doesn’t count,” and “what counts” matters
greatly to them.
For better or worse, canon and continuity are what they eat, drink, sleep, and breathe. You could probably picture several reasons for that: one being these individuals feel that their characters are like lifelong “friends” who they have “gotten to know” and they fear them becoming unrecognizable or unpredictable. Part of it is also a sense of accomplishment of collecting the knowledge of a consistent-seeming universe, one which they feel is made more “tangible” by having a single rigid continuity. This is lock-step with the 1990s mindset, which was a time when people loved to “collect” things like comics, stamps, trading cards.
Amassing knowledge of a well-defined “canon” feeds into that part of their souls, and that collection of knowledge is, in their minds, negated by a continuity that is fluid and dynamic instead one that is “set in stone” and exclusionary.
I am quite sure a lot what I am saying is resonating with certain people in this thread as they read this very post. It may even make them feel somewhat uncomfortable.
Meanwhile, we have on the other hand the younger, newer fans. These guys aren’t into collecting much of anything as they derive more value from present experiences instead of collected things or amassed fictional knowledge. This is true of millennials in particular who spend more money on vacations and social experiences than they do on consumer goods (look it up) and that plays right into why Infinite Frontier will appeal to them. Infinite Frontier is about good stories without regard to the canon, and very little emphasis on referencing the past at all.
As to explain the behavior we're seeing before us: the shift toward more isolated stories which may draw upon any history at will, and may not consistently reference one another, threatens the more aged set of fans. Most are actually okay with it though and will adapt well.
But a couple have said “they like Infinite Frontier so far” simply because DC has not yet reached the phase in which referencing different pasts has fully played out. Some who struggle to adjust cope using a bit of healthy denial, ignoring the readings that don’t fit their preferred canon (like a couple here are doing with Superman Reborn) or labelling them as a deviation, or whatever fanfic they want to invent. But then you have a scant few whose denial runs really deep who cope by devising a revisionist “headcanon” that we've somehow swapped timelines, accompanied by a total lack of any in-universe or outside universe explanation or event to substantiate it. And some (like a couple in this thread) take it a step further by going around echo chambers repeating their newly constructed "headcanon" which is that the old is actually the only continuity, desperately praying it will “catch on” and somehow become lore to everybody else. It’s all in vain though, and it’s all self-soothing.