Lecturers are not divine so cannot claim to be infallible but they are generally better informed than their students. They are also the ones setting and examining assessments so they will generally choose topics they know something about. 🙂 In all seriousness, lecturers are specialists, often experts in their field, and it is their job to help you. Please make the most of that help.
If you are discussing what foods you like or the weather then of course your opinion is as valid as your lecturer’s (unless you’re a student of Meteorology … ). If, however, you are discussing something within your lecturer’s area of academic expertise then they are likely to have a more profound level of understanding than you can be expected to have at this point in your studies. When you finish your degree you will know that your academic skills and subject knowledge have developed considerably since your first weeks at university. This is even more true of someone who has researched at post-graduate level and taught for many years.
Mechanics know more about engines than we do, plumbers know more about plumbing and doctors know more about complex illness. Oddly enough academics know more about their subject and how to study it than their students 🙂 . I’m not saying that lecturers are always right any more than doctors and mechanics are. But the student would be wise to acknowledge the value of academic experience and to benefit from it.
In all likelihood your lecturer will have to produce research that is good enough to be published in international academic journals. While this is frankly a pain for many of them, who don’t have sufficient time to research as they’d like, it does mean that reading, writing and critical skills are being honed continually in a tough academic environment. Students get the benefit of these skills in the form of lectures and seminars but also essay feedback. If you’re not confident that you could write a research paper as well as your lecturer then it would be worth at least listening to their advice.
While it is true that there are various ways of looking at literary texts it is not true that there is an unlimited variety of credible interpretations. Readings may focus on different approaches (feminist, historicist, Marxist etc) but there has to be robust supporting evidence or the reading will fail to convince.
Lecturers do not usually tell students they’re plain ‘wrong’ unless they really are barking up the wrong tree, in which case they need to be told so that they can get back on track.
If you want to ignore your lecturer’s expertise then you are free to do so but you’re going to be missing out and making life more difficult for yourself. Student life is hard enough – make the most of any expertise and help on offer!