I am curious as to your expertise in criminal law and procedure. I have 10 years at the Bar and what you are saying is totally and absolutley incorrect. These apply to the following people as laid down in Rule 2 of the same rules.
1) Criminal Prisoners: Meaning those who have been detained by Court order.
2) Convicted Prisoners: Meaning those who have been convicted
3) Civil Prisoners; Meaning who don't come under either above head.
Under law, Police/Rangers can hold you for only 24 hours (Section 61 CrPC) after which they need a Magistrate to extend the remand. Once this 24 hour period is exhausted and the M<agistrate extends the remand ("the Court order") then the persons become criminal prisoners as per clause 1 above. Thus Prison Rules apply.
You may argue that these are not ordinary prisoners but those whi were detained under Public Order Laws. And you would be correct. Unfortunatley for you in that case the have to be PAID by the Government for every day they are detained. See
http://www.punjabcode.punjab.gov.pk/public/dr/THE PUNJAB PUBLIC ORDER DETENUE RULES, 1979.doc.pdf
(Rule 8).
All in all, the Rangers did nothing that was not mandated/authroised by law and which does not happen elsewhere and Pakistan hating liberals need to find another excuse.