Personally I'd just stop offering fruit for 2 or 3 days. Sweet foods are obviously tastier to babies, they have a naturally sweet tooth, but at 7 months milk is still the most important food and your LO won't go hungry by you withholding fruit. Meanwhile try offering some of the sweeter vegetables such as puréed sweetcorn or baked wedges of sweet potato as finger food (or mash if you prefer), carrots etc.
I wouldn't go the route of downing tools and leaving your LO when he refuses savoury stuff, this starts to set up power struggles over food from an early age and tbh you just don't want them. Better to keep the whole mood light and positive. That's doesn't mean it is up to him what he eats, it only means it is up to you what is offered. Once offered he can either eat it or not. I think you might end up getting very frustrated as the months go by if you go the down tools and leave way. Also there is a slight risk that one day he might have something in his mouth when you go, so a small chance of leaving him with a choking hazard without even being aware of it.
I'm sure that after 2 - 3 days your LO will begin to accept some other foods, carbs and veg, maybe meat and fish too. Then you can reintroduce small portions of fruit.
hth