My case is a reference to a real-life, literal sitaution that I was involved with. The "opinions" expressed as why I would or would not do certain things had PLENTY of A/B testing and research done on them. Not only internally, within my company, but externally out on the open internet. Nothing I said conflicts with extremely common understandings of these UX patterns. And, far more importantly, our internal testing and research backed all of our findings up.
So when someone says "here's a better way to do your UX", they are specifically saying that they have some insight that beats out all of the research and testing I have seen on it. In which case, I am MORE THAN HAPPY to see any of it. I love to learn that certain patterns don't work the way I thought they did! Sometimes it just means they've gone out of style and we need to update with a trend. I'm very interested in making UX the most reasonable I can for the most users. So if I'm doing something wrong, I'd love to see data to support that!
What is less interesting to me is someone saying that their opinion is better without any evidence of that claim. But, hey, I'm open to new ideas: please explain to me what concrete actions I should take based on the reply I got? I should go research it because ne said it, even though it's a very common thing that is said in these discussions and I've never seen it supported? Do you chase down every single lead without asking for the minimum amount of effort to be put in by the propositioner? If this person was earnest about helping me achieve a better UX, rather than just stating their opinion out loud, why is it difficult to follow up with practical data?
The difference is, I didn't say "Here's a better UX". I said "This is an appropriate use for the UX". I didn't back it up with testing because I wasn't saying anything that needed backing up. I wasn't making a value statement, or insisting on a quality of the UX; I just said that toasts were appropriate for certain functions - not that there was no better way to handle the UX.
You, on the other hand, absolutely did make a value judgement. You said "better". And okay! I'm fine with you having a better UX! I'd love to know more! Please, provide any information you have on why yours is better!
If you need more help deciphering the difference: I was arguing against the blog author's EXCLUSIVE argument ("actually, this is appropriate, so it's not that toasts are NEVER good UX"). You are arguing for your own EXCLUSIVE argument ("the good things about this way aren't available with your way"). If you don't understand why exclusive arguments merit more evidence than arguments for maintaining inclusion (as opposed to changing to be more inclusive), I'd recommend boning up on formal logic.