Return all rows with a certain value in jsonb dictionary in Postgres
You can use jsonb_each_text (or json_each_text) function which expands outer most json object into key - value record. Here is the example query;

SELECT * FROM 
(
    SELECT
        t.id,
        (jsonb_each_text(t.dicts)).*
    FROM
        my_table t
) denormalized_values
WHERE
    value = 'walking'


And the result of the query above will be; 

| id |      key |   value |
|----|----------|---------|
|  1 | exercise | walking |
|  3 |  hobbies | walking |


&lt;&lt;fiddle>>