I have many grounds.
The first and foremost ground is, misinterpretation given to the said phrase in sec 7(3) of DP Act by Police.
A combined reading of sec 7(1)(b)(ii) and sec 7(3), clearly indicates that, a complaint can be filed by 3 distinct sets of people: 1) the person aggrieved by the offence or 2) a parent or other relative of such person, or 3) by any recognised welfare institution or organisation; but protection from prosecution is given to only one set of persons: 1) the person aggrieved by the offence. No amount of harmonium interpretation can be allowed to be read into sec 7(3), when it is not ambiguous at all.
Secondly, sec 3(1) says If any person, gives or abets the giving of dowry, he shall be punishable, there by making the parents of woman accused under this section. The interpretation given the police (and unfortunately, by 5 High Courts) is to be held valid, then highlighted test in sec 3(1) fails. Dowry givers are to be prosecuted and not to be protected from prosecution.
Please let me know if there is any legally tenable argument to unseat this position I took. Based on responses, I will bring in more grounds gradually so as to keep this conversation interactive.