Meh seems about right.
Plug/unplug is not going to destroy anything if you hook up the signals right and use a factory standard Sub-D connector using only logic and ROM that's all powered from a low-power supply or the connector itself.
There's designs out there that are powered by the port itself by means of a set of 1n4148 diodes on all signals and a nominal series resistance that don't require ultra quick data flanks that worked for those people.
Caveat: No CE/TuV will ever approve that, because it CAN destroy the buffers or control logic. Most computers have buffers.
If you want to be 100% safe you can apply some modern connector trickery by heating the GND pins and pushing them out a little bit, so that they all connect first and disconnect last, but this is more work with basically no real-world need.
What you DO have to be very careful of is boot-up. During boot BIOS and/or OS kernel may send control signals on the bidirectionals and control signals to check if a terminal printer or terminal display is there, to output logs or statistics to. So if you have outputs on your side on a bidirectional and the PC then wants to output the opposite voltage, that conflict may end in burn-outs on your motherboard. In another case the ROM might coincidentally "respond" in one certain way, making the system going into Kernel-dump sending out bunches of data on the signal lines on EPP type ports, where your ROM is also outputting something.
Although that is also not very likely, it is more a consideration than the plug-risk in my experience. So while booting the safest thing is to not have anything attached, and plug it in after you have a familiar screen (login or near-login, etc).