Barcelona fans really feel quite sad about losing Messi and even Messi has tried to extend his contract but in the last seconds Barcelona actually let Messi go due to financial problems, I think Barcelona fans understand why Messi left and they don't blame Messi at all because there really is a problem with barcelona, even if later messi returns to barcelona as another team player (against barcelona) but I am pretty sure that barcelona fans will still welcome him well, even though now messi is no longer playing for barcelona but because messi is still a legend who is able to give glory to barcelona previously.
Right now have bigger expected for Barcelona fans after rumor Lionel Messi will return back and not reach agreement extended contract with PSG, last several season Lionel Messi leave Barcelona as free agent player after not reach agreement extended contract due salary payment but seems next window transfer if still not extended with PSG I think has fewest chance will back to Barcelona.
Financial crisis and huge salary from Lionel Messi will difficult for Barcelona how to signing back Lionel Messi, many team will give fantastic offering and salary for Lionel Messi if not agree for extended contract with PSG, however become free agent player in the next window transfer have easy for any team want to sign Messi.