Good to see a decent number of people signing such a petition. At 89k out of 319m people, that is almost 0.02% of the population.
Personally, I think petitioning our would be masters is a waste of time... but if that many people sign such a petition I wouldn't doubt that 10 times that number would agree with it or at least looking at the information provided, which is a good thing.
If you are the non-petitioning type and believe that people shouldn't be jailed for owning plants, one thing you can do to help plant owners is to refuse to convict anyone of owning plants if you sit on a jury. (unlikely due to plea bargaining and harsh drug penalties... but it could happen)