Asking people what features, options, colors, etc they like and don't like about their cars for the purpose of constant improvement is an excellent example of why Toyota is rated so highly--AND has abosolutely ZERO to do with what got this whole Magilla started--the "warning" about early wear of tires. Constructive comments and feedback to Toyota are completely unrelated to a footnote warning you that you shouldn't rely on the backup camera (as an example), and you should note your surroundings--because, without it, someone WILL start a class action lawsuit because they hit something relying on the camera.
There's a distinct difference between reaching out to Toyota and telling them that you would prefer they use 50 or 55 series tires which may last longer, rather than the lower profile tires, vs pointing the finger "why didn't you tell me my tires wouldn't last 20k miles". If enough people give construtive feedback they may make a change. But merely blaming Lexus for failing to diligence your automotive purchase is not right.
If you want a performance-oriented sports sedan that competes with a BMW 3-Series, some compromises are needed--that may include sport tires. You noted that Lexus could have offered a non-sport tire option. In a focus group, you could note to Lexus that you might have preferred that option. Lexus didn't offer it to you, but you bought the IS anyway, rather than opt for another car with touring tires, such as an ES. So it wasn't that important to you then--and now that the warning has come true you are "very disappointed in them."