I wouldn't consider it either "red" nor a purplish burgundy.......more of a deep cherry pink. Even 'Rubidor'/'Olympiade', which is considered the classic weigela for chartreuse foliage has flowers that are more pink than red.....certainly not "red" like 'Red Prince' or Sonic Bloom Red.

Described as "carmine red" by the 2014 Hillier manual when I grew this I never thought of this 'Bristol Ruby' sport as anything other than a red weigela with yellow leaves - the marked redness of the flowers, in comparison to say 'Looymansii Aurea' appeared at the time to be the point of it.

https://www.bing.com/images/search?q=rubidor&qpvt=rubidor&form=IGRE&first=1&cw=1129&ch=614

Embothrium, it is interesting that you would call that color red, because to me all of those photos read much more like a deep pink than a true lipstick red. Hopefully I can see some in bloom at a garden center near me in the spring.

It's all a matter of degree, of where on the scale from pink to red one decides a shade has become red instead of pink.