Cannot establish communication through RS232 to a digital scale
The reason the connection worked from Rpi --> Scale and not PC --> Scale is because of luck ( or lack of it) : The scale expects a crossed TX and RX and since the RPi connection was of my making, I had accidentally crossed the RX and TX at the MAX232 level. So using a non-crossed cable with the Rpi worked (since the signal entering it was already crossed at MAX232) while using a crossed cable did not work. On the PC side, the opposite was happening and that is where the confusion started. In a conclusion and lesson to benefit readers, the RS232 standard was originally intended for DTE/DCE communication (T for terminal and C for communication, aka computer to modem). Later, the standard was more widely used as DTE/DTE or "Serial null modem" where the Rx and the Tx are cross-connected as such.


More configurations (with handshaking etc) can be found at the source https://www.lammertbies.nl/comm/info/RS-232_null_modem.html

So as @Tut and @Rioraxe quickly noted, the problem was with the cable, so make sure to know the type of cable you are using by testing it with an ohm meter or any other method.