Lana: Mind if I come in?

Chloe: The girl who writes for "The Pom-pom
Parade" is, no surprise, out with mono.

Lana: This week's editorial?

Chloe: My semiannual
"Where Are Our Priorities" rant.

Lana: For what it's worth, I really like what
you've done with the paper this year.

Chloe: Well, that puts you in the majority of one. I'm sorry about
the pom-pom crack. Once I hit "take no prisoners" mode,
it's kind of hard for me to shut it off.

What do the underlined parts mean? I'll just tell you that
Chloe is a journalist and Lana is an ex cheerleader.
out with mono. = a derogatory reference to a person the speaker obviously feels in mentally deficient (out to lunch, perhaps)

puts you in the majority of one = all alone in your opinion

take no prisoners" = angry, vicious mood (kill all the enemy, take none alive)
she's sick with mononucleosis
ironic: you're the only person thinking about it and approving of if

once I get in my aggressive mode
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she's sick with mononucleosis

Of course! It is so clear to me now, Marius. However, in my defense, I have heard people call stupid people 'Mono', probably in reference to their inability to put two and two together.
One more comment about "mono" - it is sometimes called "the kissing disease" because it's easily spread, so she could also be implying that the girl who is out with this disease is a bit "Friendly" with the boys.
Okay, guys, but can mono have another meaning like "single"?
And perhaps Chloe is just telling Lana "Since you're not a
cheerleader anymore you've decided to visit me - the lone one!"
Is that a possibility?
Students: Are you brave enough to let our tutors analyse your pronunciation?
That doesn't make any sense to me, no.