Very hot soapy water isn't the same as boiling water. Silicone (and glass and steel) can withstand boiling water without any problems. Unlike those materials, jelly rubber is porous so, as your toy dries from its "very hot" bath, its wet pores can become a breeding ground for mold or bacteria.
Jelly rubber also disintegrates over time. Even if people don't have an obvious tactile sensitivity to the cheap rubber (e.g. it stings) or they don't react by having a rash or other inflammation, they're still being exposed to phthalates and to the byproducts of the rubber "melting". Another side effect of this disintegration is that a rubber toy can discolor or further damage any other toys stored with it.
Plenty of companies nowadays make affordable toys out of body-safe materials. Anyone reading this thread and planning to buy sex toys should spend a little extra cash on making sure the products are nontoxic.
More info-
http://dangerouslilly.com/toxictoys/
https://www.reddit.com/r/sex/comments/184960/toxic_sex_toys_what_to_know_before_you_buy/
or just search Google for body safe sex toys.