In reply to Guido.

I've found this too as we spend a lot of time repairing sites built by agencies. The worst are those using themes from themeforest, that include the evil visual composer, plus revolution slider plugins. They're a nightmare in terms of site performance, SEO, ongoing support and updates. Divi from elegant themes I also hate. If these three developers could just disappear forever, the WordPress world would be a better place.