Casting it as an "admission" hardly makes it so - if the "thinkers" haven't figured out by now that that sort of standard is pretty much all we ever get in virtually everything we ever do across our entire lives, then they haven't thought very deeply at all. Try operating for a while based only on things you can absolutely prove to be true - you'll be dead in very short order, I can guarantee it.
When I started reading the creationist critique, I was intrigued at how reasonable some of their objections seemed as well, but I was even more surprised at how unwilling the scientific community was to actually answer that critique.
It's a fair criticism to point out that scientists do a poor job of explaining what they are up to, and what they do. But it is another fallacy to assume that, since mainstream scientists decline to answer Kent Hovind, they therefore can't answer Kent Hovind. Kent Hovind has been answered regularly and in depth by dozens of people across many years, and yet he continues plugging away with the same basic errors that he started with. How many times must the voice of reason be "willing" to answer his critiques - such as they are - before we permit them to stop trying such a futile exercise? Some people can't be persuaded of truth, no matter what, because they have some vested interest in the falsity of whatever it is under discussion.
Some people ask the same questions and raise the same issues that have been raised dozens or hundreds of times before, when the answers are readily accessible to anyone who bothers to do even the most cursory investigation on their own. How many times do we expect people to answer the same questions over and over ("If we evolved from monkeys, how come there are still monkeys?"), before we grant that they are human and prone to a bit of exasperation?
There's a subtle version of that going on with your reference to high-tech equipment that is only available to the priesthood of the professional biologist.
You object to the notion that some things are complicated, or beyond the resources of most people to do?
In the case of the present article, there has been no proof offered regarding the introduction of the parent species 300 years ago, there has been no explanation of reasonable alternative sources (migrating birds, dormant seed, human introduction, etc.), and there has been no concise explanation of the genetic connection, other than "trust the experts."
Sigh. As I said, there never will be absolute proof. You don't expect it anywhere else, and you can't have it here, either. The explanation of the genetics of the thing is qute readily accessible to people who take the time and make the effort to find it - your objection thus far is basically a complaint that nobody is spoon-feeding it to you in nice soundbite-sized chunks.
As for "reasonable alternative sources" - why should anyone take any of them seriously unless and until you have some evidence for them? If you have some alternate theory, I strongly suggest you get out there and find some evidence to support it, if there is any. At this point, my reasonable alternative explanation - that Santa Claus dropped the seeds there during his last Christmas outing - has exactly as much evidence supporting it as your proposals do - none whatsoever.