The education system in India offers a fork-in-the-road twice:
1. Grade 10 - at which point you get to choose the general direction you want to head in (primarily Arts, Science, or Commerce streams)
2. Grade 12 - at which point you get to choose a slightly more specific stream, pursuant to the stream you chose in grade 10.
Science students continue to study Physics, Chemistry and Maths until the end of grade 12 at which point they are presented with the above fork-in-the-road. To get into a college that offers an engineering degree (or any applied-sciences degree, for that matter,) you need to have a good score in PCM, i.e. Physics, Chemistry & Maths. It is in this context that your Physics & Chemistry scores are relevant.
Also, one of the basic requirements for getting into a engineering course is that you should have graduated from a Science stream. Someone who has completed grades 11 and 12 in the commerce stream can't get an applied sciences course.
I agree with you. In India, the top schools for undergraduate education are Indian Institute of Technology(IIT) and National Institute of Technology(NIT). There are 16 IITs and 30 NITs across India, each with their own campuses, faculty, etc. Both conduct two nation wide exams namely IIT-JEE and AIEEE with different formats where IIT-JEE is hard to crack than AIEEE. In both the exams, there are only three subjects - Maths, Physics and Chemistry. So, if one has to make into one of these fine institutes, one has to be good at all of these. I have seen many who couldn't get into these instis even though they were very good at two subjects but sucked at the third one.
Source: I got into one of the NITs.
Imagine an environment where PHP is considered cutting edge and where 90% of students (and 80% teachers) don't know even C properly. That is the environment we have! PHP is something that is completely unknown to teachers and considered cutting edge.
And I don't have any issues with Math. Mathematical logic is indeed required. BUT Physics and Chemistry are totally irrelevant as requirements! Unfortunately, they have 66% weight!
Anyway I completely agree that physics and chemistry should not be heavy requirements like that.