Not as any long lasting panic mode no. Again what you have an issue it seems in understanding is (again) I support being as diversified as possible. Placing your personal investments all over the proverbial map so to say. I've NEVER said someone should not invest in a 401k, ROTH IRA, or any other accounts.
Like I've said before, I have 4 stools on my chair right now and wouldn't mind adding that 5th if the offer was appealing.
My plan is to retire with more investments then I need to accumulate for living out my life. That way if any or all of them take a hit, I'll have a decent cushion maybe to ride that wave.
But BREXIT was a nice little example to use to show just how easy it is for the market to take a tumble even if I did personally feel it wasn't going to last too long. It should have been a little wake up call for you to be diversified.