The answer is pretty simple some chefs use the term in order to promote there own ROMS by putting down others for whats in them.
Here is the facts the amount of programs in a ROM does not determine its speed or available RAM only the number of options you can ultimately do with the ROM. Now this is not to say if you try to run everything at once the device wont slow down as it will. It is fine to have your ROM FULLY LOADED if that is your liking but keep in mind whatever is running at startup will eat away at your available RAM. ONCE AGAIN LOADING THE ROM TO FULL CAPACITY DOES NOT AFFECT PERFORMANCE IN ANY WAY SHAPE OR FORM!!!!