I looked at your profile, it seems you spend your days going to from plugin to plugin posting unfounded claims. Quite sad really.
After measuring loading speeds while and while not running Custom Contact Forms on a variety of hosts. It seems that your website’s server is quite slow. I implore you to check your own server’s speed, even though you probably don’t know how to do that, before insulting people’s programming. None of the tests I ran on any of those servers resulted in a 6 second latency.
However, there was a speed problem with the plugin but it is now 100% fixed. The problem was that on each page load the plugin was checking database tables for the existence of around 25 columns. The function, updateTables(), is very necessary but does not need to be run on each page load. The updateTables() function was moved from the init hook to the activate plugin hook. Now updateTables() as well as createTables() and a few other install related functions are only run when the plugin is activated.
Now the plugin is running very fast and everything is fixed.
I would encourage anyone how has an issue with the plugin to be civilized and email me or fill out the bug report form in the admin panel of the plugin, instead of trying to bad mouth the plugin. I usually respond to bug reports within a few hours, and fix the problem within 2 days.