The guys were quoting an English translation of the rules originally in Chinese.
Rounded blades on scissors make them blunt objects and ineffective for achieving their implied purpose (ie cutting things). Notwithstanding, an argument would have only led to tears (mine) and a visit to a very ugly holding cell off the airport. The argument that SYD, LAX, DFW, NRT and HND security said they are "OK" failed to impress.
And rounded blades are on items.
That other airrports allowed them is irrelevant. different places have different rules. Taipei is none of Australia , USA or Japan so would not expect that to hold any weight. There are, for example, surgical items with rounded blades - and this is different to having rounded tips