This coming week, an unsuspecting person wishing to catch a /minyan/, who walks into a random /shul /in many places around the world, might be in for a surprise. After the /Shemoneh/ /Esrei/ prayer on Sunday there will be no /Tachanun/. On Monday there will be /Selichos/; and on Thursday there again wont be /Tachanun/! Why would this be? No /Tachanun/ generally signifies that it is a festive day;[1] <https://ohr.edu/5146#_edn1> yet, no other observances are readily noticeable. As for the reciting of /Selichos/ on Monday, they are usually reserved for a fast day; yet no one seems to be fasting! What is going on?
I repeat my objections to this article from last year, when you also linked to it.
Come on. Neither Pesach Sheni nor Lag Be'omer can possibly be described as "unknown days". It's just not true. Anyone who has never heard of these days has never heard of tachanun either, and wouldn't notice whether it's being said or not. The author himself later notes that even in chu"l there is the tradition of an outing on Lag Ba'omer, though he strangely refers to it dismissively, saying there are no observances "unless one counts" this one. That's a bit like saying Chanukah has no observances unless one counts the menorah, etc. If the author wants to write about these days, let him write about them; there's no need to pretend they're "unknown" as an excuse.
I also take issue with the author's characterisation of Behab as "Days of Tefilah" on which, by the way, some people also fast. On the contrary, they are voluntary fast days, which nowadays have mostly fallen into desuetude. As fast days, those observing them say selichos and read Vayechal. Those who are not observing them don't.
I suppose that if one who is not observing them davens in a minyan that is, it would make sense to selichos with them. If there are minyanim where there are not ten fasting, so they don't read Vayhechal, but they still say selichos, I assume the idea is that it's "officially" a fasters' minyan, but it just so happens that lately there have not been enough fasters so they had to cancel the Vayechal, but they still continue the previous practice of saying selichos, like a shul that's officially Nusach Ashkenaz even if everyone who currently attends davens Sfard.
I will not be so foolish as to claim there are no communities where it has lately become the "established custom" not to fast but still to say Selichos; there are so many different customs that it's foolish to insist that *anything* doesn't exist. So I will merely say that I have never heard of such a thing. But even if such communities exist, it is seriously backwards to characterise the days as the author does. The selichos is always secondary to and a consequence of the fast, not vice versa.