Under the pressure of a relatively small number of people compared with the city’s population. I think the article’s explanation is reasonable - chaos, compared with the cities mentioned which aren’t Abbott targets.

But the article’s fair - it doesn’t lay it all at Abbott’s feet. He’s performing for sure, and doing nothing to lessen the chaos of haphazard bus arrivals to his destination cities, but gets credit for highlighting the dysfunction. The article points out that Biden has always had the power to step in to control distribution of the burden of immigrants, but hasn’t because he doesn’t want to “own it”. That would have cut off Abbott’s efforts to sow chaos in prominent cities. And it points out that dem and repub presidents since Clinton have focused on public perceptions of their approaches to immigration, rather than practical solutions.

It keeps getting worse because it’s just too valuable as a political issue, so politicians want to posture, not govern.