That is your understanding and it is perfectly reasonable not to have come across the other negative connotations before, just as some people in the past genuinely did not think using some racial slurs was problematic (however it is very unlikely any ‘proper’ Chelsea fan would be in this position).
Here is a clear Chelsea statement:
View attachment 205307
View attachment 205308
And here is more context from them. It is short and simple to understand:
https://assets.ctfassets.net/qtmbc4...246f80a7ceefcc/Chelsea_Rent_Boy_Briefing_.pdf
I have also pointed out that people close to me consider that term personally offensive and unwelcoming. Of course not everyone will agree, but over time culture shifts and most fans follow those norms, for example we condemn racist chanting. Some are clearly not there yet with what many consider to be homophobic chanting, but perhaps discussions like these can throw more light than heat on the issue.
So, there is the counter argument to your own personal understanding. As I said before, If you choose to stick to your guns and use the chant then so be it, but hopefully there is now more understanding of how some others may not like it.