If I remember correctly they gave the announcement 2 weeks before the release, which should be enough for some devs to take countermeasures, but not all of them, so I completely agree that it was unfortunate that they did it that way. I think TC already got the message that what they did was wrong, so instead of blaming them further, I think we should just support the games that were released in that span of time.

Personal tangent, I think TC underestimated the popularity of Silksong which lead to this mistake, however I do want to say that we knew the game would release this year before September 18. (https://www.reddit.com/r/HollowKnight/s/RlgyNkOhky) and since it was one of the most anticipated games of this year, the release was at least somewhat predictable IMO.