This is a matter you should probably give a lot of thought to.
By saying what you have, you have crossed into the other persons territory/space - which belongs to them alone unless they give you permission to enter.
If your attraction to male genitals that you are speaking to strangers in the manner you did, then maybe some professional insights would help. You are lucky the person didn't "go after you" regardless if what you said was meant as a complement.
There are a lot of people out there who would just like any opportunity to "get a faggot" - and you don't know who they are.
Those kinds of comments you can save for when you are someone(s) you know and the environment is such that saying such things is appropriate i. e. a group possibly have sex together, or you and another person.
Would you want someone making comments to you of a sexual nature without your permission. It may not have seemed like a sexual situation to you but one you made those comments you altered that enviornment in both instances.
I am not trying to intrude in your privacy and you should not be intruding in other people's privacy without their permission. I do not know your age, nor should I.
But give serious thought to what you are doing and see if logically it really seems like appropriate behaviour on your part.
A side issue - why is the size of some one's cock such an issue. There are a lot of attractive average size cocks around that work just as week at the "giant ones."
If size is going to be and or is an issue you - think about it.
The real critical issue is not the size of someone's cock and or balls, but who they are as a person.