It's extremely common for people to be unhappy with how a WordPress plugin adds front end resources to their site. If a plugin needs CSS, it'll slap in a <link> to that stylesheet. Or a <script>. Or link up images.
Plugins do this because it works. It's damn important for a WordPress plugin to work, even in adverse conditions.
In optimizing front end performance of a site, reducing the number of HTTP requests is a huge thing. It's my site, I want to decide and control how front end resources are being handled.
So perhaps we can suggest how WordPress plugins should handle external resources: