“Unprofessional” might be the wrong term to use here. After all, thousands of sample packs and libraries are sold everywhere on the net for this exact purpose: to give upcoming (and even seasoned) producers some good quality building blocks to work with.
Now, there should be a personal sense of satisfaction brought by the work you’ve actually put in making your music. And while using many loops can definitely sound great, does it make you feel great? You should be definitely proud of the music you make, and develop your own signature sound. Using loops is certainly not wrong, but it’s also not very creative.
This is like the same issue we commonly see in graphic design. There are thousands of free and paid vector graphics (think of all the flourish, curly things and paint blotches you see all over the place). These can look great in “generic” designs all over the place, but do they bring on a sense of identity? Not really.
Use the building blocks all you want. But take the time to watch tutorials on how to actually create the sounds you’re after – they’re readily available on Youtube and laid out in a way that makes it really easy to follow the instructions. But beyond recreating the same thing the tutorials teach you, why not take some extra knowledge away from it? If the guy tweaked a particular LFO in a particular way, try alternative LFO shapes. Follow the tutorial, but use a different waveform on the oscillators. Think outside the box, understand what’s happening to the sound as processes are applied – you’ll learn way more by doing this AND experimenting than by recreating.
On the flipside, one of the best ways I’ve come up with learning how to make music has been to attempt to recreate – as closely as possible – the tracks I know and love. This is a good exercise. You won’t be releasing this stuff, but there is SO MUCH you can learn from this exercise!