First of all, the catalyst is a DIbutyltin dialurate. Not a tributyltin. The tributyltin has the potential to do some nasty stuff as you and your reference states, but this is not the ingredient we are discussing. And claiming that tributyltin is an inevitable impurity would be just bad chemistry on the manufacturing company's part considering it wouldn't catalyze the silicone polymer properly, be a waste, and isn't listed on the MSDS and is thereby just speculation.
Then comes the issue that dibutyltin dialurate it is used in surgical/medical grade equipment. That in of itself is enough for me.
Then comes the fact that it is insoluble in water. (hydrophobic) And that it is encased in a solid matrix of a hyrdophobic material. (The silicone polymer.) So water moving over it isn't going to release it to make it bio-available.
Then there is its usage in PVC production. And I see no evidence to stop using PVC in terrariums,vivarium, aquariums, my house plumbing etc...
Then there is its usage in food production as a "de-worming agent" for chickens. And that resins containing it are approved by the FDA for food contact.
So yea TRIbutyltin has potential toxicity issues that are well reported. Dibutyltin dialurate isn't quite as nasty (8 fold less so), has a wide range of uses, and isn't worth fretting over in the context of this usage. Not in comparison to the many other possible toxins/leachate people use in their tanks, like large volumes of calcium hydroxide from improperly cured concrete/grout.
So with no less than thousands of dart-frog tanks built using this material, the fact that its used in fractions of 1%, is bound in a hydrophobic matrix, and is used in materials seen in the hobby since its very beginning (pvc), its just not worth worrying about and especially not worth trying to convince people to purchase a lower grade product that smells much worse.
So again, the "whole organotin thing", in this context and usage, not a believer.