Thank you for all your replies. Here I will explain what confused me.
1) I mistakenly identified
"that they said was" as a restricted relative clause, which requires
"the" before
"government" (which in turn comes before
"that") and now I see that it is not the case.
2) I know this use of the
"a" article when you "refer to a kind of, or example of something" (
http://www.edufind.com/english/grammar/Determiners3.cfm):
the mouse had
a tiny nosethe elephant had
a long trunkit was
a very strange carIn the past I may haven't paid enough attention to the usage of
"a" in the middle and before
"that" as in the original sentence so I failed to identify
"toward a government that" being that case.
Now with all you help, I perceive the original sentence in the following way.
...anger about the crisis and resentment toward a government (what kind of/type of government, bad, good, etc?) that they said was more preoccupied
Thank you again.
Best regards,
Olex