G-d is not a problem for me.
Are you telling me that G-d told you not to spread your beliefs and faith?
No.
Then you not being able to say who said Jews can’t proselytize is a problem for you because you have a belief without an authority or any logical reason for that belief. It appears you are taking it on faith.
Knock it off with the psycho analysis would you
It's wearing on the nerves.
Then answer the question.
Who is it that forbids Jews from proselytizing?
There's no proselytizing in Judaism.
When people use that term they associate it with Christian and Muslim history of expanding domination by force and through the various means of sticking their noses into ones life to convince him of some none sense.
While the Giyur of Judaism is a concept that exists in none of those dominating Christian and Muslim religions, one can understand it more easily by looking at the traditions of various Native American tribes where the 'conversion' is into the tribe rather than religion.
What does it mean?
Basically a French can convert to Islam and stay a French Muslim,
or a German can convert to Christianity and stay German Christian.
But when an Arab goes through Giyur he separates from the surrounding and the rest of nations, joins the tribe , becoming completely Israel.
It's not like getting a new nationality of the state/country, let's say an American Kurd,
but the nationality of his tribe, i.e. becoming a Kurd...or in this case Israel.
There's no commandment to do Giyur to anyone, but there're many rules that seek to prevent or otherwise convince that it's a burden and a danger and unnecessary. The motives of the person have to be checked very carefully, to make sure there're no alter motives, that's it's not out of fear and danger, not for material gains or status, not marriage with a current partner and lastly not a "spur of the moment" of a spark that may dim after a couple years.
The Torah also tells us that during times of a Mashiah (anointed king), like during the reign of King David A"H and King Shlomoh A"H - there's no acceptance of Ger's.
This is also applied during times when Israel's hand is on top.
Now why is all that?
Because our purpose is not to make everyone like us,
but to correct the Kingdom of G-d in His world, knowledge of G-d,
and for that there's no need for all of humanity to accept 613 commandments, rather what is necessary is knowledge of G-d of Israel and acceptance of the yoke of 7 commandments given to Noah.
Christianity and Islam are religions wired for export abroad so the world converts into them, while Judaism is confined to specific borders seeking that the world KNOWS G-d.
G-d made sure we stay a tiny tribe only to Himself, so that we don't even consider marketing like jeans.