Not intentional propaganda (as far as Western media goes), just the usual cut-and-paste reporting with no particular directives from the editors to look more deeply into the story. It may reflect a bias, but in this case most likely an entirely unconscious bias. This is quite different from the state-originated propaganda (especially coming from deeply authoritarian governments such as that of Russia) which is very intentional and often more or less scripted and templated.
Meanwhile let's remember that the arrest (and draconian sentencing) were in themselves a very deliberate form of propaganda. It's not like the various Russian agencies could begin to care about a $51 donation. They did what they did for certain reasons, one of which was to send some very specific messages -- on one hand to the U.S. government; but also to their own people, both inside the Motherland and abroad.
That latter message being: "We're watching you, wherever you are, and however small and unimportant you think you are - so don't you even begin to think of crossing us."
This case was probably particularly appealing to them in part precisely because the charges could be presented as borderline plausible (rather than being simply trumped up from scratch). Even if they would ultimately prove to be quite flimsy if evaluated by the standards of countries with actual working justice systems, as seems to be the case here.
It's just another part of their playbook.