In your Washington Post example,
They were more angry with Washington and intense in their desires for a smaller federal government and deficit.
I think that the "more angry" phrasing may be intended as a smoother read for the parallel construction ('more angry ... and (more) intense'), although if that's what they really intended then the second 'more' should probably have been included. Even so, though, perhaps the editor there felt that mixing a single-word comparative form (angrier) with an absolute form (intense) was something to avoid.
An interesting bunch of examples, and correctly grouped.
However, the three groups are not monophyletic. Briefly,
Group A is an example of what linguists call a "rule conspiracy", where a number of independently motivated processes "conspire" to produce a similar surface structure. Georgia Green discussed them in her paper [Green, Georgia M. (1970) 'How Abstract is Surface Structure?' CLS 6, 270-281].
What's come to be called the 'Green Conspiracy' includes such structures as
- I shot him dead.
- I buried him alive.
- I found him alive.
- I need him dead.
et cetera, with very different meanings.
The point, if any, is that there is a limited number of surface structures that English prefers, and there are many more different ways to get from meaning to one of them. I.e, these structures do not represent a single kind of meaning, but rather several. They are all, of course, regular (in much the ways suggested by the OP), but which rule gets used is arbitrary and idiomatic.
EDIT: a little more about Green's paper, which seems to be difficult to find.
This is from a paper by Goldsmith and Huck commenting on the theories involved.
Green (1970), noting that a variety of different semantic structures could be associated with the same surface syntactic construction, argued that there must be a limited set of syntactic “target structures” into which the transformational rules map their
representations. The sentences She shot him dead and They buried him alive, she argued, both share the same superficial syntactic structure, but crucially differ semantically as to whether the adjective indicates a pre-existing state or a result. As she pointed out, “natural language syntax is free to utilize mechanisms by which a large and diverse set of logical and semantic relations are somehow squeezed into a small number of surface structures” (Green 1970:277). In that paper, she referred to such mechanisms as “conspiracies.”
Group B is a conflation of several varieties of Raising and Equi,
with different kinds of tensed and untensed complement clauses.
Group C consists of several examples of the rule of to be-Deletion
(p.9 in the Transformation List).
Best Answer
In typical narratives about past events the past simple is the default tense. However, if the speaker wishes to convey the ongoing nature of the past action or state, then the past continuous can be used. For example:
You might also have encountered the past continuous more often because it is commonly used as a stock phrase to formulate a polite request.
is more tentative than: