why is my processes in task manager showing ports like 100028,103904 ?

It's a Process ID (PID) not port number.

Microsoft has made it quite clear that we should attach to significance to the size of process id numbers. While the numbers are unusual I don't think they mean anything, at least none that has been documented.

In the past Windows tried to keep these values low but this was only for cosmetic reasons. Maybe that has changed?

In Linux a process ID cannot exceed 65535 but that is not the case in Windows. I have heard of process IDs over 400000 in busy servers.

Edit: Port numbers , as used in TCP/IP networking, are limited to 65535 but a PID is something very different and not related in any way.

A PID is an arbitrary number that uniquely identifies a process or thread. When the process or thread terminates the number is eventually recycled. It is officially documented as a DWORD, meaning it can have a value from 0 to 4,294,967,295. Officially a PID can be any value in that range. Currently it is a multiple of 4 but that is merely an implementation detail that could change at any time. In Windows 95 PIDs in fact had values in the high end of that range but as Task Manager did not show PIDs that was not well known. In early beta versions of Windows 2000 PIDs often had high values, causing concern that this indicated some kind of error. So in later versions Windows tried to keep the values low, purely for cosmetic reasons. That policy may have changed. But don't expect to see documentation regarding changes in undocumented behavior.