I think the larger parts of the debris are tracked pretty carefully, not to mention the active satellite paths. So, a launch can be calculated to miss (or be missed by) the things we track.
On the other hand, once a launch vehicle is well clear of the atmosphere (where debris density is extremely low because it can't stay there for even one orbit), the small pieces of junk that are not tracked, or even trackable, might do damage to something like a heat shield surface, which might cause a catastrophic failure during reentry.
This problem is only going to get worse as more and more counties launch their own space vehicles, often on small budgets and with limited capabilities for things like engine restarts while in orbit (where there is no "bottom" in a tank and ignition may be an issue).
And any sort of a war that involves disabling adversaries' satellites could jack this risk into the unacceptable range for manned flights.
Some international rules might help, but we have all seen how effective the U.N. isn't at making countries behave ethically.