I am here answering my own question for anybody that can encounter the same problem. The issue was related to .bashrc directives. My .bashrc file included commands to source Intel's *.sh files and set default compilers (e.g.: export FC = /opt/intel/bin/ifort). By commenting out all the export and source commands related to Intel Compilers, MATLAB starts.
WORKAROUND #1: Instead of editing .bashrc every time, it is enough to preload one Intel library: the symbol is actually undefined in libirng, but it is defined in libirc.
Therefore it is enough to edit .bashrc once with:
LD_PRELOAD = /opt/intel/compilers_and_libraries_2018.2.199/linux/compiler/lib/intel64/libirc.so
This does the trick and MATLAB starts normally.
Also a workaround to avoid editing the .bashrc file every single time. In case workaround #1 didn't work, wrap MATLAB initialization in a .desktop file like this:
Exec=bash --noprofile --norc -c 'exec YourPathToMatlab/matlab -desktop'
This invokes the shell but in a way that it ignores the bashrc specifications. The -c flag makes it execute the string that follows and thus launch MATLAB.