To the OP (and anyone else who cares to read - although TLDR at end):
It is not that I would say that you are being100% Unreasonable - but I do think your efforts to deter a possible burglar with radio are futile.
I downgraded ( and - sized) a few years ago, to an unfamilar area, that I soon discovered to be - um - undesirable (a mistake, and moved in a hurry....).
The garden is about 50 feet long and after a gate sections off the lawn and closer to the house, is open after another 12 feet to an access road ( and the back of another road beyond).
From my days of having house-pets, I have ALWAYS left a radio on quietly (cannot be heard next door or outside), and sometimes even the TV or a CD on repeat. This was not to deter entry; that actually never crossed my mind. I also leave lamps on in every room except spare room, and plug-in nightglights in the hall/porch.
One cold February night, I returned at 9pm after putting horses to bed (yes, this was pretty routine but I had not lived there very long.... and had done so for years in previous village). Into the living room and I am crunching in smashed glass from the patio door - which faces the rear garden.
Whoever broke in could not have cared less about my radio, TV, lamps or anything else..... all of which could have indicated that I was actually still IN the house. The (tall) gate partway down the garden had been kicked off it's hinges before they could even get to the property. The Police (yes, these were the days when they would attend) made me laugh when they said that the "perp" would have "knocked on the door to see if anyone was in" ....... 
I still chuckle when I think of that remark.
On the question of noise between houses; I think that it is a fair reason for your neighbour to have a word with you, especially as - unless I have missed something - the radio is or was against the adjoining wall.
I actually purchased a digital piano so that I would not disturb my neighbours, as that was the only wall I could put a piano against. Similarly, I try to wait until they are out to use my lockdown treadmill, unless I can pass that noise off as an overweight hamster.
THEY, on the other hand, have had weed-smoking parties throughout lockdown, use their garden as a toilet when feeling lazy - and, wait for it, actually play THEIR music through an amplifier!!
I have had six different neighbours since living here - and the best one was a chap who paid the rent but lived at his new girlfriend's, so I heard nothing. Until some kind of beep-beeping started and I couldn't get him to come and stop it (by leaving him a message at the shop where he worked), so had to ask the landlord to access..... Result was that he did move out, but not before calling me (together with the landlord - also my landlord - an interfering c-word). There have been others but I have digressed too far I know.
TLDR
OP - the radio will not prevent burglars. Trust me, I know.
Be nicer to your neighbour. But the name calling on here is awful and not necessary.
Over and out.