After removing aftermarket security system it will not start

Hello, I am Danny.

Quick question first. Can you use your phone to take a picture of the plug/harness and upload it here? It would help us identify and we can attach the appropriate wiring diagrams for you. Thanks for using 2CarPros.
Danny-

https://www.2carpros.com/articles/how-to-check-wiring

To add a question, If you turn the key on and push it to bump start it, does it start and run? That would help narrow down if it is just the starting circuit or if it is more involved.
Plus could you add the make and model of the items you removed, sometimes you can look those up and find install instructions or wiring information.

The wiring needs to be connected properly not just twisted together next. Can you take shots of under the dash so we can see where the connector plugs into?

Okay, looked at the wiring and pulled up the install sheet for that unit. It is a basic alarm with a plug in starter cutout. So there is a plug in the starting circuit under the dash and this unit would have had a short jumper wire plug that installed in there to keep the starter from operating. If that is still in place then it is very likely the item that is causing the no start. The plug you have should be for the optional alarm Honda had. Not used without the OEM so that is why there is nothing to plug it into.