E2guardian ssl mitm

Hi All,
I'm new and apology me for stupid question..perhaps ..
I installed LEDE on an old PC for router/firewall... I want set web filtering content with e2guardian and squid but I have an issue:

If I set e2guardian with blacklists -2M rows- ( from urlblacklists) I decommented an include statement in bannedsitelists, e2G dosn't start.
If I store few lines into domains file it works.
Is there a max size for domains lines??

Another question.. is there a reason --enable-sslmitm is not compiled to "yes"??