that's written on the back of the first two Synergy records, 1975 and 1976, an inverse nod to Queen's "This album was created with absolutely no synthesizers"
c.f Human League - “We are the Human League, there are no guitars” (Phil Oakey, voiceover on “Dada Dada Duchamp Vortex’, which is 1977 I think) and also "We're the Human League.
There are no guitars or drums played on this record" on 'Dance Like A Star" which is also 1977 I believe.
I don't think Queen though were anti synths, though, so much as trying to say "all these amazing sounds you're hearing on the record, that's our wizardry with guitars and the mixing desk"
they don't seem like Luddites
plus there was quite a lot of synth-ery in mainstream rock before Synthpop...
Pete Townsend had a big collection of synths
Pink Floyd "On the Run"... Hillage...
there's loads more examples
sort of makes you wonder why Synthpop was such a big deal
i guess because it wasn't so player-ly, so obviously musical in the Old Wave sense... and synthpop also had the mechanistic post-Moroder rhythm aspect... it very much didn't rock, didn't groove