Crazy and sad. I have been taking this as a new habit in the last months: saying God bless you instead of Thank you. And I mean it too, it is weird how many people get angry or look like they want to trow up when I say that.
The hate on God and all the teachings of Jesus Christ (like love, gratitude, being humble and peaceful) is a religion by itself these days.
If this is not prophecy word by word being fullfiled, I do not know what it is:

"But know this, that in the last days grievous times shall come.
For men shall be lovers of self, lovers of money, boastful, haughty, railers, disobedient to parents, unthankful, unholy,
without natural affection, implacable, slanderers, without self-control, fierce, no lovers of good,
traitors, headstrong, puffed up, lovers of pleasure rather than lovers of God;
holding a form of godliness, but having denied the power therefore. From these also turn away."

2 Timothy 3:1-5

And, of course:

"Then shall they deliver you up unto tribulation, and shall kill you: and ye shall be hated of all the nations for my name's sake.
And then shall many stumble, and shall deliver up one another, and shall hate one another.
And many false prophets shall arise, and shall lead many astray.
And because iniquity shall be multiplied, the love of the many shall wax cold.
But he that endureth to the end, the same shall be saved."

Mathew 24:9-13

It's a stupid rule, and I'd probably tell the teacher to get lost, but it isn't a violation of the first amendment.

Freedon of speech. 

This is such a rediculous rule. How does saying a rule breaking word end you in suspension? Worst school ever.

Freedom of speech protects you from Congress enacting laws that would get you arrested or penalized for expressing your opinion, as long as what you say doesn't violate other laws like libel, slander, copyright and others.

Freedom of speech is not a license to say anything anywhere.  An institution that you participate in can have rules on what is acceptable to say, for example a company usually has a code of conduct and breaking it can lead in getting fired or disciplinary actions.  Schools have rules, and a teacher can set classroom rules and use several disciplinary actions if they are not followed.

Ah but telling someone to do the "f" word is a form of oppression. Your trying to express anger at someone or make them feel horrible by saying that. Point out one person who means to do harm by saying "bless you." Even if you don't believe in God and Jesus Christ it's not like someone is insulting you by saying something kind to you. Then again, I am reminded time and time again of what the Bible says about the world and the way it will treat Christians:

Matthew 10:22English Standard Version (ESV)

22  and you will be hated by all for my name's sake.  But the one who endures to the end will be saved.

1 John 3:13English Standard Version (ESV)

13 Do not be surprised, brothers,[a] that the world hates you.

John 15:18-19English Standard Version (ESV)

The Hatred of the World

18 “If the world hates you, know that it has hated me before it hated you. 19 If you were of the world, the world would love you as its own; but because you are not of the world, but I chose you out of the world, therefore the world hates you.

Ok, In-School Suspension is not such a severe thing. It is more similar to a detention, but inside normal school hours and probably just for 1 or 2 days.

1. Students will be assigned to In-School Suspension and/or Detention for good and sufficient reasons including, but not limited to:

a. Behavior which adversely affects the safety and well being of other students;

b. Behavior which disrupts a class or school sponsored activity; or

c. Behavior prejudicial to good order, discipline, and safety occurring in class or school sponsored activities.

... so if the girl was told by the teacher "saying bless you is against classroom rules", whether stupid or not, and the girl started acting out against the teacher then this seems like a normal outcome.

Isn't tenesse in the bible belt? I'm surprised the kid was canonized for is actions

Bless your heart for sharing this story..

am i gonna be banned now? lol