Is the first Amendment dead?

Two people from an activist group where fined 1000 dollars or 6 months in jail for laughing at Jeff Sessions.
“Barry and Bianchi were each found guilty of parading/demonstrating and unlawful display but were found not guilty of disrupting Congress.”
Exactly what is an unlawful display? Words? Laughter? I can see being kicked out but a fine or jail for being in a building that tax payers pay for.
How is this not a violation of the 1st Amendment? Did anyone face jail time for screaming liar at President Obama addressing Congress and the Nation?
How is this not like some dictatorship?
http://www.nbcnews.com/news/us-news/activist-faces-jail-time-laughing-during-sessions-hearing-n754326