If people are sick of reading about stuff just stop taking part. You have 100% control over what you read. Simic Ascendancy isn't going to get banned just because you didn't tell someone to shut up on the internet.
In general, the indefinite article ("a" or "an") in a condition on a card means "at least one". Examples of this include—
Worship ("If you control a creature..." means "If you control at least one creature..."),
bloodthirst N ("If an opponent was dealt damage..." means "If at least one opponent was dealt damage..."; see also this thread) (C.R. 702.54a), and
Myojin of Cleansing Fire ("...as long as it has a divinity counter..." means "...as long as it has at least one divinity counter...").
In a condition, where "at least one" is not meant, alternative wordings would generally be used, as found in Deadly Wanderings and Tidal Influence (in its Oracle text [C.R. 108.1]), for example.
The later example i guess could apply if you had two or more creatures but maybe you see what I'm saying.
Anyway, thanks!
In a condition, where "at least one" is not meant, alternative wordings would generally be used, as found in Deadly Wanderings and Tidal Influence (in its Oracle text [C.R. 108.1]), for example.
However, the foregoing generally doesn't apply—
Only few Magic cards have the phrase "only one", and they include Meddle, Quicksilver Dragon, and the Unglued card Once More with Feeling in its Oracle text (C.R. 108.1).
EDIT (Jan. 2): Added paragraph.
EDIT (Jan. 16): Correctness edit in view of changes to the Magic Tournament Rules with Rivals of Ixalan.
EDIT (Mar. 1): Added paragraph.
EDIT (Feb. 21; Mar. 10): Clarification.
EDIT (Sep. 11): Correctness edit.
EDIT (Mar. 27, 2021): Edited generally.
EDIT (Sep. 1, 2022): Correctness edit. One rule was renumbered in the meantime.