Because we are logging a TLS message in the command line processing code itself, the logging occurs prior to the parsing of the --logpath parameter. This means any log messages go to stdout instead of the log file. This is apparent if you start mongod with --logpath:

/data/ent/mongo: ./mongod --replSet foo --dbpath /data/db/r0 -v --logpath ./t.log
2018-11-27T16:13:56.372-0500 I CONTROL  [main] Automatically disabling TLS 1.0, to force-enable TLS 1.0 specify --sslDisabledProtocols 'none'

(and then no other terminal messages appear)