The issue with them is that while yes, you -can- clean it, you will never be able to clean it -thoroughly-. Because it's porous, it will soak up anything and everything it can, which can still be there even after cleaning. This can then lead to bacteria proliferating on the toy, which would then go into your body. Always using a condom with a jelly toy creates a barrier to prevent any transference of bacterium, whether you share it or not.
Also, most jelly toys are made under some pretty shady situations. You don't know exactly what chemicals and such went into making it and what leeches out of it in use.
There's also the issue that many people out there are even allergic to jelly toys, causing them burns. Think of it like chopping up a bunch of chiles with your bare hands, then touching yourself. It's not fun.
In addition to all that, jelly toys simply are not made to last. Their materials are not substantial enough to really be used longer than about six months. They degrade really quickly.
Things like pure silicone, yes, they cost a whole lot more, but they are made to last a lifetime, as long as you treat them well. They are completely non-porous, so they won't absorb anything at all. You can sterilise them so they -can- be shared without the use of condoms, if you want to share.
You can get a jelly toy for, what, ten to twenty dollars? It's a nicer price tag compared to a fifty dollar silicone dildo, but the silicone dildo, which would be a one-time investment, would last you many, many years. The jelly toy would need to be replaced every six months at most, which, if you initially spent fifteen dollars, would be thirty dollars a year; sixty dollars in two years. So, for two years' worth of toys, only, you'd be spending the same amount for a toy that should last you your whole life, provided no accidents come to it.
