I am a parent (and an IT professional) who advocates the same thing - Computers should be in "public" view especially where children are using them. I very strongly advocate that even where not in public view the bedroom is an entirely inappropriate place for them and would always argue for a home office.
Bedroom should be "for bed" they are for sanctuary and getting away from distractions - it is simply not an appropriate place for a distracting and addictive machine like a computer. The temptation to stay up for 'just one more...' is incredibly strong and something that is immediately obvious if a child is NOT in their room.
Technical measures are not a proxy for parenting. As an IT professional myself I have a very thorough firewall, live updates, extensive traffic decryption capabilities, and the ability to break into my children's apps or devices at any time should they give me reason to.
Your technical skills may well exceed your parents and you could feasibly disable a monitoring system that they could install; certainly as a teenager defeating a technical measure would have merely presented a fun and interesting (though short-lived) challenge for me.
Openness keeps you honest and you have to be honest with yourself at this point - no matter what you say today, you absolutely are going to encounter if not actively seek out porn at some point in the future. Curiosity is going to get the better of you, it's going to happen like night follows day. There will be less temptation if you know that someone else might walk in at any moment even if you don't think they've been paying attention to what you're doing.
Porn is not the only kind of inappropriate content, the internet is a communications medium and there are many 'radical' or undesirables who have an extensive online presence. There are cyber-bullies etc.
Computers are inherently anti-socialasocial tools even before the advent of the internet, having a machine like that in your bedroom gives you a strong pull to shut yourself off from social interaction. Even if there are other people in the room, that is still a form of social interaction and it's important. Programmers and gamers are particularly susceptible to this. I appreciate the distraction argument, but ultimately half the point is for you to be distracted and to have to deal with people sometimes.
Ultimately, it's their house and their rules when you have your own place and you're paying the mortgage etc then you can set your own rules, but in this instance they are doing what is best for you, not what will best please you.