A lot of people and small companies are saying or doing things to manipulate the market, but because they are on internet social platforms people think it shouldn't be taken seriously, and caught offenders not punished for it.
With so many doing it the only practical solution to fix it is to force a new law for the markets so it's harder for people to access the market. Otherwise the only other solution would be to regulate parts of the internet and social media platforms, which could lead to control over other areas of the internet. Worst case.
In the case of GME and AMC, it has more to do with people looking at short selling of stock, and lack of transparency. You shouldn't be able to short a large portion of the total stock that is being traded, that seems like manipulation to me. Many people that are still buying and holding GME do so, because they believe there is still a large short position out there, and that those short will be forced to buy a large portion of all of the stock being floated at once. This may or may not be the case, but lack of transparency creates a situation where if these people are right, they are pretty much guaranteed to make a big profit.
In the case of other "meme stocks," it pretty much comes down to the fact that a lot of people are investing in companies based on criteria other than fundamentals. I don't think you can really stop that without more or less restricting people's ability to trade in general. I don't really see there being a good case for telling people "Yeah, we are restricting your ability to buy publicly traded companies."
As to restricting peoples speech on the internet, what do you think we should be able to restrict?
"We have a new process, and we believe this will lead to future profitability,"
"We have X, and we think that's good,"
What do you think is happening that is crossing the line?