I suspected this half a year ago and everyone thought I was a "conspiracy theorist"

You are perfectly know that most "conspiracy theories" are just spoilers. :)

I want to 3D print pikes but cannot find a 3D printer large enough or a plastic material strong enough to support writhing 250lbs corpse.

You could do it. Kind of. In your 3D editor split your pikes in parts you could print. Glue them after printing in whole thing. Use this model to sand casting your pikes from whatever material you like. Works perfect for me for complex aluminium car parts. See no problems why it whould not work for you for steel. And you could cast as many pikes as you need for your fellows using that 3D printed model.

If you are advanced enough in engineering you could try to combine 3D printer with MIG welder.

Also, it is not a problem to build large 3D printer. It is even not expensive now. Problem will arise with speed of printing that will depend on diameter of extruder jet for FDM printers. Some enthusiasts even was able to print buildings from concrete.

Even with current level of 3D printing tech, I personally find 3D printing extremely useful even for domestic use. Saved me a tons of money and time, and often I was able to print a plastic spare part for broken plasic original that was better and solved problem with that part forever. Unlimited sharing of 3D models for common things among people also helps a lot. Printing NLA parts resolve the problem with programmed obsolescence by manufacturer. Sand casting metal parts using printed model also works perfectly, but I thinking about obtaining some written off x-ray scope to control quality of castings, few times I got cavities inside castings and had to cast and replace part again, thankfully model was already done so that was fast.

Perhaps you could get government subsidies to turn old windmill blades into corpse spikes? Helping the planet and all that jazz!