According to HIS account they were having what reads as a relatively reasonable conversion (one which he was entirely in the right) until he dropped the line 'I'm going to do what I want to do and you're not going to like it' then called her dog to him with treats...
I'm not shocked she called the police for help and neither should he if thought about it. A lot of women who were on their own with a stranger in a park after feeling threatened. So actually saying something that sounds like a threat is going to cause problems. The guy seems like a nice man so I genuinely think he was oblivious to her perception of the situation and possibly still is.
Again, not an excuse for her to jump to using race - yes she knows that it will be perceived as adding to the urgency to her call to the police. However if you don't think he escalated things with his actions and caused her to freak out and involve the police I'm not sure you care to understand the nuances.
On the 'victim blaming' point, in the UK we have a concept of split liability so an accident may be one persons fault or both in any apportionment. It's way too simplistic to always say one person is 100% right and the other 100% wrong. In this incident the public interest is entirely in the dog being off the leash (admittedly a local issue) and using the police to manage the situation. Which now more information has come out we can see that he contributed to her need for assistance, which is legitimate given the perceived threat, though clearly she used his race both as a means to intimidate him and try to create urgency with the police which is both clear racism and criticism and social consequences are warranted for that.
I would just suggest to every man to be careful approaching women on their own in a park, especially if you end up going some weird stuff like saying 'I'm going to do what I want and you're not going to like it'.