Too many radishes have been sown! They are too close to be big and fine.
This is how it can go when you sprinkle seeds directly from the seed bag.
It is a good idea to pour some seeds from the bag into the hand and take a few seeds at a time with the other hand. Then you can put the seeds more precisely into the wound groove. It takes a little longer, but then you do not have to thin so much - and it also takes time.
Pull up so many radishes that there will be a few inches between the plants. Press the soil down firmly on the plants you leave behind.
Nothing is so bad that it is not good for anything. There were a lot of lovely radish sprouts for the salad bowl.
Incidentally, the sprouts could also have been planted with care elsewhere. Then there had also been fine radishes out of them.
Remember to water gently when you have finished thinning out.