It's an autohit and critical.
The language is: " the weapon attack is a critical hit", not the "hit is a critical".
Parsed, the rule is "the attack is a hit and that hit is a critical"
Or then there's the other way to look at it...
The actual rule on automatic hits has the subject header 'Rolling 1 or 20':
Sometimes fate blesses or curses a combatant, causing the novice to hit and the veteran to miss.
If the d20 roll for an attack in a 20, the attack hits regardless of any modifiers, or the target's AC. In addition, the attack is a critical hit, as explained later in this chapter.
If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target's AC.
Then, the rule in the subject header 'Critical Hits' is as follows:
When you score a critical hit, you get to roll extra dice for the attack's damage against the target.
Thus.. you can easily also parse it as that only 1s and 20s cause automatic misses and hits... since that is precisely the language they used to describe automatic misses and hits. A 1 is an auto-miss, a 20 is an auto-hit. The use of the term 'critical hit' occurs
after the language describing the auto-hit, and doesn't
modify the rule, it's in
addition to it (since it states "In addition...") Thus, it is completely rational to believe that auto-hits and critical hits are in fact two separate states... and it just so happens that a 20 counts as both. But does not absolutely guarantee that other rolls that qualify under the term of "critical hit" also fall under the term "auto-hit"... since it specifically calls out the 20 in the subject header and the first line of the rule as the only number that auto-hits, and that "critical hits" are specifically called out in their own section as extra damage (and speaks nothing about actually hitting targets)
If all "critical hits" were absolutely 100% meant to be parsed as "auto-hits"... why doesn't the book write the header as "Rolling 1 or a Critical Hit", and start by saying that
some hits are so powerful that they automatically are considered to hit and do extra damage, regardless of any modifiers or the target's AC? And then state that most characters do a critical hit when they roll an unmodified 20 on a die roll, but that some characters might have a larger critical range? And then they could describe the rules for the extra damage.
But they didn't do that. They started by calling out the '20' specifically as an "auto-hit" and then tacked on the addendum that this 20 was also a "critical hit" (which they later define only as extra damage dice".) Now yes... I know that they use the word "hit" within the term "critical hit". And if this was the very first edition of the game they ever wrote, maybe you'd have a point. But the phrase "critical hit" has existed in the game for decades, and as someone stated up above, that specific term has become a "term of art" in the game, and no longer meant to be taken as 'noun + adjective'. After all... the game uses the term "Armor Class"... but I don't see anyone stating that obviously Armor is describing a type of Class within the game, to go along with the Fighter, Rogue or Cleric. Nope... "Armor Class" has become its own specific term of art... just like "Critical Hit" has.
That being said... do I genuinely care one way or the other which way anyone rules it? Nope, not in the slightest. If Mike thinks that all critical hits are auto-hits... good for him. Any if anyone else feels the same way, hey, it's no skin off my nose, go nuts! But with all the talk of making sure we "parse the language"... I thought it was important to note that we weren't just pulling this opinion out of our asses... we were "parsing the language" too and just happen to come up with a different result.