@DrDeth did take the moderation to heart and provided a better example of the same latter on, to his credit:
Where the original link was to a general SCOTUS FAQ with 15 (!) different possible questions. Yes, one of which was a very short section, quoted in my example above by @DrDeth. It is absolutely better when drawing on a general source to quote the specifics.
If the cite/link had been only about the history and legal backing of the number of justices, it would have been better as an un-excerpted link, but it’s generally better to give your fellow posters an idea of what the cite says rather than click to get it all. Especially when it’s a general, rather than a specific site.
It’s also serves a good purpose, because you have a chance to make sure your cite says what you think it does, which is the concern @What_Exit explicitly addressed.