Ah, unpredictable. You'll agree with me that a result can be more, or less, unpredictable, no? "Kamala Harris will win NC" (more unpredictable) vs. "Kamala Harris will win CA" (less unpredictable)... What discriminates one result as more unpredictable than another? The flattening of the probability distribution function, of course.
Squirm as you might, the flat probability function is at the core of randomness, there's no escaping that.
1. Flattening of a probability function isn't the same thing as a completely flat probability function. That's just not how language works. Language is rarely taken to the logical extreme.
For instance, let's talk about the word "tall" as used to describe people. You can define tall operationally as the number of meters required to traverse a vertical plane starting at a person's feet and ending at their head (I know this isn't a plane per se, but I don't remember the right word. Surface?). But that doesn't mean that tall only refers to the tallest people. Indeed, to the contrary, tall usually has an implied reference to some sort of cutoff. You can put the cutoff in different places depending on your purposes -- maybe tall is someone whose body is longer than average? Or 80th percentile? 90th? -- but in the end, the word applies when the threshold is met. It doesn't continue further.
So too with random. That randomness is connected to flat probability distributions does not imply that only perfectly flat distributions are random, as the word is used in ordinary language. There's a threshold, and once crossed, the word applies.
Most adjectives I can think of work this way, because logical purity is not an important or valuable function of ordinary language. To the contrary, language is most useful when it's generalizable. If I apply for a job, and my resume is thrown out because HR rolls a 3d6 for each received resume and tosses any that come up 5 or less . . . well, I think I'd have a right to complain about that, and in formulating that complaint, I'd use the word random, as in "it's not fair to toss out resumes randomly like that." The function of the word is to contrast that selection process with something principled. I don't think anyone would dispute the use of the word there, nor in any similar way that might violate technical randomness as you've defined it.
In ordinary language, in fact, random often means "unimportant" or "arbitrary." For instance, if the employer tosses all resumes for people whose last name starts with the letter F, we'd call that exclusion "randomly." We'd say, "they have so many applicants that they can toss resumes out at random." That there was a method to the madness isn't really important, because the method is not considered acceptable.
2. I guess the main point here is that ordinary language and technical language have different functions in our society, and the desirable qualities of each are different. When you demand that ordinary language follow technical language -- there's just no justification for it. Computer scientists don't have special powers to change our language just because they define concepts with math.
If ordinary language borrows from technical language, the case for your position is stronger. For instance, DNA did not exist as a term until it was coined by biologists. So in this instance, biologists might be more justified in insisting that DNA refer to specific molecules in cells. But generally, they don't. People say, "doing the right thing is no longer in Boeing's DNA" even though obviously a company can't have DNA. Basketball analysts refer to players' gravitational pull -- meaning that their abilities, especially shooting abilities, require the defense to keep multiple players near them at all times. Obviously this isn't the same as gravity. And yet, many of those analysts are trained in math or physics and they don't object.
But in the usual case where technical definitions borrow from ordinary language, I just don't see how it can possibly be appropriate for a technical community to insist that its definition of the word has supplanted other usages as the correct definition. Are we going to need a new word for a small round dessert snack often filled with chocolate chips, because programmers defined "cookies" to refer to bits of information?