Your “understood meaning” might be peculiar if it includes Twitter and not Microsoft. It’s hard to imagine that the source or even Gizmodo’s editors meant it that way.
Twitter is “big” in terms of social cachet, which matters for the free speech debate, but isn’t going around and gobbling up and fortifying verticals and horizontals the way the others are. And it’s that perpetual blob-like absorption of industry that worries economic regulators, not free speech stuff.
Your frustration might be rooted in your own idiosyncratic way of classifying things (as a tech worker? as a social media user?).