Most of the errors you will see in any page speed checker including Google Page Insights have to do with the server and/or usage of the theme and not with the theme itself. Things such as compressing and resizing images is something that needs to be done by the user as well as minifying and caching are things required on the server end. You’ll need to setup your site and server correctly to archive a good score. if you notice an error coming strictly from the theme let us know so we can fix it!
Important Notice: Google PageSpeed Insights is generally acknowledged as broken and even sometimes suggesting fixes that are not needed or have already been fixed by its own PageSpeed module. We recommend instead using more reputable speed checkers such as gtmetrix or webpagetest.