Yes, I believe marijuana makes you "sloth-like." Really, it's one of the qualities many users are looking for. A calming, slowing of their minds and bodies. Unfortuantely, I've seen too many people who have allowed marijuana to make them sloth-like, doing little, thinking little, caring little and overall being sloths.
When you ingest marijuana, your perception and movements become slow and muted, and it does make you awfully "sloth-like." All you have to do is look around a room where there are individuals are ingesting marijuana to see the sloth-like effect it has. Sloths are known for their extreme laziness and lack of motivation, and this isn't unlike the effect marijuana has on the human brain.
Due to marijuana status as a schedule I drug in the USA, any research on the long-term marijuana is extremely limited and there is no clear evidence that marijuana will make you lazy. Studies about marijuana often have sample sizes that are far too small to make any constructive conclusions about the long-term effects of the drug.
The average marijuana user does not use to the level of acting like a lazy slow moving sloth. That is a myth propagated by people under the false impression that it is a gateway drug, again not based on any credible scientific evidence. Chronic users of any substance, including caffiene and alcohol suffer effects not everyone experiences.