Hi,
Each installed extension may load its own assets, there’s no other way to make the theme/plugin extensible – for example, the Marketplace extension loads styles required for displaying orders, payouts, etc. – including these styles to the core HivePress plugin would be less efficient (since only a small percentage of HivePress websites use Marketplace). This way each website keeps only JS/CSS files that are actually used and the codebase is not bloated.
We try to keep HivePress as lightweight as possible, e.g. we avoided CSS frameworks like Bootstrap and styled everything in pure CSS (it’s the same with JS, we keep libraries to the minimum).
If you want to reduce the number of loaded files please merge & minify them using any preferred caching or optimization plugin, the resulting CSS file will be much smaller than expected, many other themes load the whole Bootstrap or even all the styles for third-party page builders by default.
Hope this helps.