The concept of "bullpup" doesn't suck, but there are some terrible bullpups out there with questionable ergonomics and limiting architectures from the 70's and 80's like the AUG, FAMAS and SA80.
The terrible ergonomics mostly come from design by committee syndrome and ease of mechanical design/laziness at engineering - things like "cross bolt" safety ( AUG, SA80 ), terrible fire control lever ( SA80, FAMAS) placing gas regulator next to supporting fingers ( AUG ), weird magazine release ( SA80 ), terrible places or complete lack of places to put on Laser pointer + light ( AUG, FAMAS ). No matter how much they are modernized they are still stuck with some of these issues, because of the basic architectures of the system.
X95 is pretty much the only battle proven bullpup with the ergonomics done right, with enough estate for accessories. There are some interesting firing solutions that are not easy with conventional rifles but totally fast and practical with X95. There are also some situations where the use of bullpup is infinitely easier than even a SBR like MK18. The down side of bullpup tends to be the heavier weight and non-adjustable LOP ( bad for using "scopes" with a fixed eye box and eye relief if the user add layers or armour or gear), and from a conventional shooting technique perspective, some adjustments are needed. A lot of people don't really want to invest time on the system or just too stuck on what they have been doing for years.
But as the Gurhkas have shown, one can use a SA80A3 to beat the C7A2 1-meter stick when used properly even at the most conventional shooting matches.