More accurately, restricted borders with the restrictions based on what will objectively benefit the country most while upholding human rights in the process. "Open borders" is a misleading term, to say the least, not least because of the GOP's misuse. It's also worth noting that the GOP efforts to over-restrict border passage have played a significant role in encouraging crime, which they've then used to justify restricting things more, which encourages ever more crime, which...
Yeah, moving on.
This is fairly certainly closer to the truth - and likely understates the issue at hand, no less. To risk delving into these matters because of their relevance to the Republican excuses to block Ukraine aid...
It's not just the large donors. A large majority of illegal immigrants are employed by Republicans - for example, it's estimated that
about 40% of farm laborers in the US are working illegally now. The
actual issue in political play was not actually about immigration or legality. Rather, it was more about Democrats being willing to leverage the government so that farm workers are treated as people. People who are essential workers, no less, to the foundation and success of our county. This would normally involve paying them a living wage, for example. Republicans, especially the Republican politicians from more agricultural-based states, have consistently sabotaged efforts to treat these people as people, so that they can be better exploited by Republican business owners (with similar effects in play, albeit less pronounced, among the rest of the employers of those who lack legal status). For more general reference, the slave trade would likely still be alive and well if not for current cultural norms suppressing it. The factors that drove it still exist and there are plenty of people who would welcome its return if they thought that they would benefit from such.
Further, the whole border crisis scaremongering is largely an artificial crisis that has its roots in the efforts to prevent farm laborers from being treated as people. It's become a political tool largely created by and then immensely exaggerated for political purposes by Republicans. If you want a really short version why "GOP demands bad," it's because they seem to almost inevitably be aimed at making the actual problems at hand
worse in the bigger picture and to further GOP efforts to sabotage the nation and then leverage that for political gain.
If you want some specifics,
H.R. 2 would seem to provide some.
Besides the more direct sabotage things, to poke at an example of a
wonderfully kind GOP demand that they've packed in -
Ahh, the GOP's rallying cries to save the kids. Ahh, their totally honest claims to want to save the victims of human trafficking. Oh, why won't we think of the children!
Now, with a bit more context to work with, Biden HAS stated that there's willingness to compromise for the sake of Ukraine aid. That Ukraine aid is being tied to an extremist demand to give saboteurs
everything they want, including stuff like that, is little more than a demonstration of bad faith, though. For the Republicans, of course, it's likely a win-win, though, given that even if it's a lose-lose for the US, they can pretend to be actually trying to do something about the problems that we face, nevermind that it's likely to generally make things worse.
Now, why are they targeting Ukraine aid in particular? That's harder to say, but there are a few things that can be pointed at as clues. Trump and all the myriad and unfortunately submissive connections he has to Russia is a pretty obvious one. The Republican politicians actually driving the targeting have largely been quite pro-Russia in line with Russia's "God, Guns, and hating Gays" line of courting of the extremist Right-Wing. There's the authoritarian angle, of course, that has often exalted Russia in so many ways for justification and would really, really hate for Russia to flat out lose, on top of the constant embarrassment of Russia being exposed as overwhelmingly weaker than they wanted to pretend. There's the political contrarianism that likely arises from demonizing the Democrats to the point where agreement or compromise is largely counted as a bad thing, no matter what. On the political side, they also want to deny Democrats any "win" at all, as a general matter.
On the propaganda side, they have made fine use of the "Russia is overwhelming and cannot be resisted" mindset that they've encouraged. They've made use of the relative lack of compassion that conservatives tend to have for those they label as "the other." They've made use of the fear based short-sightedness and selfishness about money that they've long encouraged, nevermind that in both cases, the danger and losses are pretty well guaranteed to be significantly greater in the future if action is not taken now.
It's not for nothing that so many saw Republican politicians as a very real threat to Ukraine aid long before most Republicans were willing to admit such. Those like me were hoping to be wrong. Those like Russian propagandists have been trying hard to prove such right.