You can remove the feeds from the RSS Feeds page by modifying your styleguide.html file in your template folder, located at /templates/{your-template}/styleguide.html. You will need to access this file via FTP. There should be a section of code similar to below that you can remove:
(Note: this is taken from the Architecture template, if you are not using this template it might be slightly different code).
<h3 class="tplcond-ifhascategoryfeeds tpllang-CategoryFeeds">Category RSS Feeds</h3>
<ul class="tplcond-ifhascategoryfeeds CategoryFeedList">
<li class="tplrepeat-categoryfeed FeedLink "><a href="#"
target="_blank" class="tplvar-feedpage-url-href tplvar-feedpage-label
tplvar-feedpage-indentstyle-styleprepend">Category
Feed</a></li>
</ul>
If you remove that code, visit your control panel, go to 'Design' then 'Website Design' and reload your current template (there is a button there you can click), the category RSS feeds will no longer appear on your RSS Feeds page.
