In order to read the Check Point firewall logs in plaintext, you need to use the fwm logexport command.
The export takes a great deal of time, especially if you are converting loads of them.
Therefor you should set the SSH timeout to a greater value than usual and run a script along the lines of the following:
[Expert@HostName]# echo $TMOUT # Display current timeout
[Expert@HostName]# export TMOUT=14400 # Set new timeout
[Expert@HostName]# for logfile in $(ls 2017-0*.log);do fwm logexport -n -p -i $logfile -o ./exportedlogs/$logfile ;done