Here you can find a website about the monument. It was erected in 2008: https://www.geschichtewiki.wien.gv.at/Denkmal_Für_das_Kind_-_Rettung_jüdischer_und_nichtjüdischer_Kinder_1938
I know this small monument very well. I lived in Vienna from 1997 to 2015 and since 2016 I live in St. Pölten, and about once a week I travel to Vienna and when I arrive at Westbahnhof, I see this bronze boy sitting on the suitcase. I read the text a couple of times, but I never realized, that there might be something wrong. In fact I always interpreted it this way:
Gewidmet ...
- ... dem britischen Volk in tiefster Dankbarkeit.
Sie haben die Leben von 10 000 jüdischen und nicht-jüdischen Kindern gerettet, die zwischen 1938 und 1939 vor der Verfolgung der Nazis nach Grossbritannien fliehen konnten.
- ... den sogenannten „Kindertransporten“
But you are right, this is not what is really written on the plate. The punctuation makes »den sogenannten „Kindertransporten“« unambiguously a part of the sentence starting with »Sie haben ...«. And in this sentence a dative object at the end makes no sense.
So, the inscription is grammatically incorrect. Maybe the intention was to write is as I interpreted it, but they didn't. Maybe they had a first version that was correct and then someone changed something and the result was what we see today.
btw:
At Vienna Main Station, the biggest railway station in Vienna, (3 km away from Westbahnhof) there also is a monument that had a wrong inscript when the station was re-opened after 5 years of reconstruction in 2014.
Here are pictures of this sculpture after they removed the original inscript: https://www.austriasites.com/vienna/bezirk10_markusloewe_im_hauptbahnhof.htm
And this was the original inscript (photo taken by me):
There are two errors is in the last two lines of the long paragraph. (Wrong grammatical case and additional letter in a word.) ORF (Austrian Broadcast Company) also brought a story about this error on their website: Rechtschreibfehler am Markuslöwen
Maybe both inscripts (2008: Wiener Westbahnhof, 2014: Vienna Main Station) where written by the same "expert"?